What Jon Lester Has Left

Jon Lester’s experience in the postseason has been marked mostly by success. He’s made 21 career playoff starts and recorded a few important relief outings, too. In those games, he’s produced a 2.55 ERA and 3.62 FIP. In five World Series starts (plus one relief outing), Lester has pitched 35.2 innings, struck out 34, walked just eight, and conceded only eight runs (seven earned). He’s what one might characterize as a “big-game pitcher.”

The thing about so-called big-game pitchers, however, isn’t so much that they rise to important occasions, but rather that they simply replicate the performances that have brought them to the big stage in the first place. For over a decade, Lester has done just that. Tonight, however, the Cubs might require a little bit more of Lester.

In 2,366 regular-season innings over more than a decade, Lester has produced a 3.61 FIP. In 148 postseason innings, the 34-year-old lefty has a 3.62 FIP. Look at some of his other stats from the regular season and playoffs over the course of his career.

The numbers for Lester are pretty much the same across the board in the regular season and playoffs. His postseason ERA is lower than his regular-season mark due mostly to the .241 BABIP he’s recorded in the former. His slightly lower strikeout and walk numbers indicate that hitters have made more contact against Lester in the postseason, although it’s quite possible that some of that contact has been of the weaker variety if batters have traded in strikeout avoidance for power.

Lester has also always had good defenses behind him. The Red Sox recorded the second-highest UZR in baseball between 2006 and -14, while the Cubs rank second by that measure since the start of the 2015 season. If those clubs opted to prioritize defense in the playoffs, some weak contact and good defense could help to explain some of that disparity. Whatever the particulars, Lester has been roughly the same pitcher in the regular season and in the playoffs throughout his career.

That, unfortunately, isn’t great news for the Cubs tonight, as Lester has just authored the worst full season of his major-league career. It’s not too difficult to peer into his stats and determine the cause. Here are his walk and strikeout rates the past few seasons.

Pitchers tend to lose velocity over the course of their careers, and Lester is not immune to that trend, either.

From 2009 to -13, Lester was regularly hitting 94 mph with his fastball. From 2014 to -16, he averaged about 93 mph with that same pitch. Lester entered the 2017 season having averaged 230 innings over the previous four campaigns — including a roughly 240-inning effort in 2016 en route to the Cubs’ first World Series since the election of Taft. In 2017, his fastball velocity dropped below 92 mph, and it has stayed down there this season.

In addition to the troubling declines in strikeouts and velocity, the years have also yielded an increase in walks and homers. After conceding 53 home runs in 600-plus innings from 2014 to -16, he’s given up 50 dingers over the past two years in around 360 innings. His HR/FB rate actually declined in 2018 compared to 2017, but that number doesn’t show that the number of batted balls hit in the air off Lester increased by more than eight percentage points. This is likely a byproduct of increased four-seam fastball usage and decreased usage of the sinker.

But wait! Jon Lester produced a 3.32 ERA this season. That’s really good, right? Technically it is, yes. In this case, however, Lester’s ERA hides the deficiencies of his profile rather than illuminating the virtues. In the 2018 regular season, Lester conceded a .290 BABIP. That’s a bit better than major-league average. His 80.3% left-on-base rate, however, represented the eighth-highest mark in baseball. While good pitchers tend to record higher strand rates, Lester’s number is well above his career average of 75.2%.

It’s possible Lester buckled down a bit with runners on base: he recorded more strikeouts and walks in those situations while also allowing fewer home runs. There’s some indication, in other words, that Lester was a bit more careful when difficult situations presented themselves.

The data seem to support this point. With the bases empty, Lester went to his four-seam fastball 47% of the time, and this is where he threw it.

With runners on, though, his four-seam fastball usage dropped to 41% with a lot more pitches out of the zone or on the corners, as this chart from Baseball Savant shows.

The extra care Lester seems to have taken with runners on base might explain some of the discrepancy in his numbers, as Lester’s 3.75 FIP with runners on base would have resulted in double his 1.6 WAR on the season if he could pitch like that all the time. If we continue to follow this theory, we might conclude that Lester can still be pretty close to the pitcher he once was, but he might not have the stamina or strength to do so all of the time. The good news for Lester and the Cubs is that, tonight, he only has to be strong for a single game, and Lester has been a more deliberate and better pitcher over the final month of the season.

Here are Lester’s five-game rolling FIP and ERA marks this season.

Note the gap between ERA and FIP for what is essentially the first half of the season and then the poor numbers in both statistics for much of the second half. Over the last month, though, Lester has put together a fantastic 2.39 FIP and 1.52 ERA heading into the playoffs. His strikeout rate of 25% and walk rate of 7% mirror the numbers he posted in 2016, when the Cubs won the championship. Lester’s velocity hasn’t been any better, and aside from featuring the cutter a bit more and lessening the change, the pitch mix has been close to the same. His plate-discipline numbers haven’t changed too much either.

It does look like he’s made two alterations over the past month, though. First, he’s pitching much more slowly. Before September, Lester took 22.4 seconds between each pitch, but that figure has increased to 24.6 seconds in September. He went from being a quick worker for most of the season to slower than league average for the final month. Another difference is that he has begun pitching inside more to righties. This is where his fastball went to righties for the first five months of the season.

And this is where those pitches have been located over the last month.

Perhaps Lester has watched Cole Hamels succeed by going inside and has followed his fellow lefty’s lead. Maybe he has noticed hitters were crowding the plate. Regardless of the reason, Lester has gotten much better results on the fastball against righties, going from a 5.5% whiff rate, 11 homers, and a .236 ISO on the pitch in the first five months to a 8.6% whiff rate, no homers, and an .053 ISO on the pitch in September. Tonight, look for a slow, deliberate Lester to be careful with the Rockies hitters. If he gets a little help from the home-plate ump, we could see another big performance from a big-game pitcher. Even without a ton of help, if Lester can repeat the success he’s had over the last month, the Cubs might get another crack at the Brewers.