Every season, we brace ourselves for the inevitable decline of baseball’s stars of yesteryear. Unfortunately, we’re all getting older, and despite their rare talents and athleticism, major leaguers eventually lose production. But while each individual has their own rate of decline, generally speaking, we know a fair amount about how age affects hitters’ abilities: A typical player peaks around age 26 and gradually declines afterward in what we know as the age curve. For those fortunate enough to stick around into their late 30s. that decline becomes quite sharp.

The basis for the age curve is the difference between a player’s performance across two different seasons. The choice metric for hitters tends to be wRC+, because it’s adjusted for league average and should be less impacted by league-wide trends and fluctuations from one season to the next. The chart below shows an age curve for players using data from the last 10 seasons, preceding 2021:

The shape of the age curve makes intuitive sense, for two reasons. The obvious one is that the primary skills needed to succeed in baseball (eyesight, strength, agility, etc.) decline as the human body gets older. Another, however, is that players only remain at the big league level if they’re successful. Whether it be due to injury, a slump, or even a little bad luck, a decrease in a hitter’s performance is an inevitability before they decide to retire (or the decision is made for them). Read the rest of this entry »

The Phillies’ rotation hasn’t been a total disaster this season. Zack Wheeler is a top Cy Young candidate, and Aaron Nola has held his own as one of the league’s best starters, with the two combining for 10.8 WAR. But the rest? Zach Eflin went down in mid-July with a knee injury before getting surgery earlier this month. Vince Velasquez spent nearly two months on the injured list with a blister and was recently DFA’d; he now wears a Padres uniform. Spencer Howard had his own sophomore struggles before being traded to the Rangers at the deadline. Enter 26-year-old left-hander Ranger Suárez, who, after picking up the slack in the bullpen and briefly filling in as the team’s closer, was called upon to step into the rotation.

Suárez has been remarkably consistent since being stretched out as a starter, going at least five innings and allowing two earned runs or fewer in each of his last six starts:

During that stretch, he has only given up one home run. He’s been prolific in that regard all season, having allowed just four homers total and boasting a minuscule 0.26 HR/9 rate over those last six starts. If we extend that to the beginning of August, when he first took the mound as a starter, that becomes an even more impressive 0.18 HR/9 over 49.2 innings pitched. Not only does he seem to have the home run thing figured out, but he also doesn’t give out many free passes either: He’s issued no more than two walks in each of his last six games, good for a 5.6 BB%.

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As the end of the regular season draws near, the Wild Card race in the NL is as tight as it comes. The Dodgers currently control the top spot, while the Padres, who held onto second for most of the year, have faltered in the face of adversity, going from 91.7% playoff odds on July 27 to 24.2% as of today. That has left the door open for the Reds and Cardinals, with the former riding a torrid August and withstanding a slow September for a 36.2% chance to make the playoffs (though the latter currently leads in the chase for the second wild card by half a game).

Cincinnati’s success this season is in large part due to contributions from players like Joey Votto and Wade Miley. One unit that hasn’t helped, though is the bullpen; Reds relievers carry the fourth-highest FIP (4.69) in the majors and account for just 1.0 WAR. But in the last month and a half, the bullpen has shown some improvement, albeit modest, with a 4.40 FIP since August 1 and a 4.02 mark in the month of September, which ranks 11th in baseball during that time. That improvement has been particularly noticeable in the late innings:

All that is despite a closer situation has been fluid, to say the least — one riddled with injuries and poor performance throughout the year. Back in the offseason, the Reds surprisingly sent incumbent closer Raisel Iglesias to the Angels for middle reliever Noé Ramirez, betting that their stock of young arms and less expensive veteran alternatives would make up for his departure. The plan backfired. Iglesias is following up his excellent 2020 with a career year in which he’ll challenge previous career highs in saves and strikeouts, and his WAR this season is nearly twice that of the entire Reds relief corps.

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The Yankees snapped a four-game skid on Wednesday against the Angels to avoid a sweep and stay two games ahead of the Red Sox in the AL wild card race. Gerrit Cole was brilliant, striking out 15 en route to his 14th win of the season. Two-out singles from Luke Voit in the third inning and Brett Gardner in the fourth plated most of the runs for the Yankees, with Aaron Judge adding insurance with a solo shot in the eighth.

Perched atop the lineup was DJ LeMahieu, who reached base three times and scored the first run of the game. It’s been a bit of a down year for the veteran second baseman, who earned MVP consideration in the 2019 and ’20 seasons. Not known for his power before that former season, he caught the power bug immediately after joining the Yankees, slugging 36 home runs in 871 plate appearances, good for one home run every 24 trips to the plate. Those aren’t huge power numbers in today’s game, but it’s a much higher frequency of home runs than he managed hitting in Coors Field half the year — three times as often, in fact.

This season has gone very differently in the home run department. LeMahieu leads the team in plate appearances (575) and games played (126) but has gone deep only nine times, a rate that’s much more in line with how he hit prior to coming to New York. So what about his performance has changed?

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The Astros bludgeoned the Mariners on Saturday in a game that was over by the time the fifth inning was complete, when Houston owned a 12–0 lead and win probability odds of 99.9% (the final score was 15–1). That game marked the 19th time in August that a team had won a game by at least 10 runs, the most in any month so far this season — and we still have a week left to go before September. Naturally, the non-contenders that sold at the trade deadline or sat still have different priorities at this stage of the season compared to the postseason hopefuls. But how much of an impact does the deadline have on the game’s competitive nature?

You could try to measure this with run differential. Prior to the trade deadline, the average margin of victory in a game was 3.54 runs; since then, it’s gone up to 3.75 runs. But the average increasing by a mere 0.2 runs per game is not a monumental change. Similarly, you could look at two teams that held deadline fire sales — the Cubs and Nationals — and look at their post-July 31 performance. Chicago is down three runs and the Nationals 1.2 in terms of run differential per game, almost entirely due to pitching and defense. But those are extreme examples, and aside from Max Scherzer and Craig Kimbrel, the impact talent that both dealt away was mostly on the position player side.

Rather than just rely on anecdotal evidence, let’s take a probabilistic look at these outcomes. To test whether or not there is statistical evidence for the trade deadline creating measurable disparity, we’ll form two sets of discrete probabilities: one based on games through July 30 (prior to the trade deadline) and one based on games afterwards. Any games with a resulting run differential of greater than or equal to 10 runs will be grouped together.

Given the small increase in average run differential between the two periods, it’s no surprise that any change in probabilities is pretty small. But focusing on the left and right boundaries, you can see the differences that we’re looking for. While one-run games are still the most common, they’re happening a bit less frequently than they were before the deadline. The incidence of games decided by at least 10 runs, meanwhile, has gone from 3.9% of games pre-deadline to 6.0% after it. (Interestingly, run differentials in between the extreme values are pretty mixed.)

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The White Sox have built a commanding lead in the American League Central. They’re now 10 1/2 games ahead of second-place Cleveland and have a 99.9% chance of going to the playoffs according to our Playoff Odds. They were heavily favored to win the division going into the season, but the club has had to overcome some significant adversity (most notably early season injuries to Eloy Jiménez and Luis Robert) en route to the secure position they currently hold. And even beyond injuries, the roster was not without its questions, with one big one being how Dylan Cease would perform in his first full season in the rotation.

Cease’s 2020 campaign produced mixed results. On the surface, his 4.01 ERA, 5-4 record, and 44 strikeouts across 58.1 IP was decent. But he drastically outperformed his expected statistics, and it was hard to imagine he could maintain that ERA given his elevated walk rate (13.3%) and home run rate (1.85 HR/9), not to mention his 6.36 FIP. Cease has always had great stuff. As a prospect, his fastball graded as a plus to plus-plus pitch, with his breaking ball sniffing 60-grade territory; the question was how well he could control and command his repertoire. And while his 2020 peripherals suggested his performance this season would regress, there was a lot of optimism surrounding Cease prior to the start of the season. In spring training, Yasmani Grandal stated, “I feel like if we get him to where we see him going, this guy could be a Cy Young finalist — he could possibly be a Cy Young winner.” Read the rest of this entry »

The playoff race is heating up and for teams still competing for the postseason, the stakes are the highest they’ve been all season. The spotlight shines especially bright on high-leverage relief appearances in this environment. Unfortunately for the Padres, their All-Star closer Mark Melancon took a small step backward in yesterday’s matchup against the Athletics. Melancon entered the ninth with a two-run lead but allowed two runs on three hits and a walk. The A’s went on to win 5-4 in extras. Despite the setback, Melancon has been one of the best closers in the league in 2021, converting 32 of his 37 save opportunities and leading all of baseball in saves. This season, however, has seen a ton of blown leads in late innings. In the past two seasons, save conversion rates have plummeted, diving from a stable range of 66-70% from 2002-18, down to as low as 61.7% so far this season.

At first glance, it’s easy to point to the expansion of the active roster to 26 players and an influx of injuries as the reason for baseball’s poor performance in closing out games. Save opportunities are being distributed much more widely than in the past. The chart above shows that the drop in save conversion rate actually begins in 2019. The days of multiple workhorse closers meeting the 40-save benchmark are gone. Even getting 40 save opportunities has been elusive for all but a handful of pitchers:

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Last Friday’s trade deadline was one for the ages. If you haven’t checked out all of our analysis here at FanGraphs, I highly recommend you do so. Most of this year’s swaps were of the prospects-for-free-agents-to-be variety, meaning it will take years to assess who got the most out of a trade. Hindsight is 20-20. Even when the Dodgers famously dealt Pedro Martinez for Delino DeShields, it was somewhat defensible at the time, though of course we all know how that ended up. And so in the wake of the deadline passing, I thought I would check in on how a seemingly irrelevant deal from the 2019 deadline is working out: the Angels acquisition of Max Stassi. The Angels are on life support at the moment, having dropped two of three to the Athletics over the weekend to fall below .500. Our latest projections give them a 1.1% chance to make the playoffs. But without the offensive output from Stassi over the past two months, those odds would be even lower.

Since his return from the Injured List on June 1, Stassi has been on a tear, emerging as a quality bat from an unlikely position. His 170 wRC+ is the seventh-best mark among hitters with at least 100 plate appearances over that stretch. He leads all catchers in wRC+ during that span, along with a handful of other categories, including slugging percentage.

As a catcher, he’s not getting the plethora of plate appearances that hitters at other positions get. He’s only eclipsed 200 plate appearances once, in 2018, when he played in 88 games for the Astros and hit .226/.316/.394 for an even 100 wRC+. He ended the year with 2.8 WAR mostly due to his superior skills behind the plate. In 2019, Astros sent him to the the Angels in exchange for two long-shot prospects in the aforementioned deadline deal. He’s a back-up catcher, or at least, he has been up until now. He thrived in a small sample as recently as last year when he slashed .278/.352/.533 with seven homers in just 105 plate appearances. He’s following it up with an even better campaign in 2021. So how has Stassi gone from a glove-first backstop to one of the league’s best hitting catchers? Read the rest of this entry »

This year’s edition of baseball has produced some fascinating hitting performances. We’ve written a lot about Yasmani Grandal and his unprecedented batting line (a 134 wRC+ despite hitting .188). He’s done that in part by swinging at just 30.2% of pitches that he sees in ‘21, lowest in the majors by a wide margin. Max Muncy has also been incredibly selective, offering at just 35.4% pitches, the lowest rate of his career. These players have found that swinging less helps their game, but generally it’s not a trend that we’re seeing across the league. If anything, league-wide swing rates have increased (albeit marginally); this season’s 46.8 Swing% is the third highest since 2000. For every Muncy, there’s also a hitter who likes to swing at just about everything. Salvador Perez and Tim Anderson, for example, have swing rates of 60.3% and 59.3%, respectively.

The outliers are certainly interesting, but just how little can a big leaguer swing and still get away with it? What we’re talking about here are O-Swing% and Z-Swing%. By themselves, these are telling statistics, as hitters with a high O-Swing% strike out a lot more than those with a low O-Swing%.

For context, a 5% increase in O-Swing rate on average results in an increase of 1% to strikeout rate. This relationship is even stronger when it comes to drawing walks.

So far in ‘21, a 5% decrease in O-Swing rate on average results in an increase of 2% in walk rate.

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The season’s first half led to some nice surprise rookie performances. Yermín Mercedes took the league by storm in April, hitting for a 1.113 OPS and 206 wRC+. Adolis García rode an incredible stretch in May, during which he slashed .338/.376/.700, to his first All-Star appearance as a reserve outfielder. Late to the party is Cleveland rookie Bobby Bradley. Called up on June 5, he has thrived in his second opportunity in the big leagues, having slugged 10 home runs in 119 plate appearances. He cruised into the break hitting .240/.336/.577 with a wRC+ of 143, tied for second with Jake Fraley among all rookies with at least 100 plate appearances:

The door opened for Bradley after the departure of Carlos Santana in free agency and the more recent trade of Jake Bauers. Bradley wasn’t exactly raking in Triple-A (his slash line was .196/.266/.485 at the time of his call-up) but he must have impressed Cleveland’s coaches and front office enough during his time at the alternate site and spring training to earn the opportunity. Read the rest of this entry »