The A’s Continue to Bullpen, This Time With Trevor Rosenthal

While it’s not quite the cakewalk that the NL Central projects to be in 2021, the AL West is up for grabs this year. The Astros project as comfortable favorites, but that’s just one team. The Rangers and Mariners aren’t likely to be competitive. That leaves room for the A’s and Angels to take a crack at the division. On Thursday, Oakland took a stab at it, signing Trevor Rosenthal to a one-year, $11 million deal, as Jon Heyman first reported.

If you glanced at our list of the top 50 free agents, you won’t find this deal particularly odd. Projector emeritus Craig Edwards saw a two-year, $16 million deal for Rosenthal, while crowdsourcing came in at two years and $13 million. One year and $11 million is a better deal than those, but not by a huge amount, and Jeff Passan reported that he turned down multi-year deals in that range. Rosenthal’s contract includes deferrals — he’s due $3 million in 2021, $3 million in 2022, and $5 million in 2023. That’s essentially $11 million, though; at a 2% interest rate, it’s the same as $10.75 million in 2021. Don’t focus too much on that — it’s mere window dressing, and the interesting part of the contract is Rosenthal himself.

Rosenthal is hardly a standard free agent, and the fact that he’s signing a perfectly ordinary contract is in itself remarkable. This time last year, he had reported to camp with the Kansas City Royals on a minor league contract. The deal wasn’t for the league minimum — it guaranteed him $2 million if he made the major league roster, with another $2.25 million in incentives. Earnable money is different from a guaranteed contract, however, and if he’d had a bad spring training or tweaked something before camp ended, he’d never see the money.

With the benefit of hindsight, that deal was great for both Rosenthal and the Royals. He appeared in 14 games and struck out 21 opponents, good for a 37.5% strikeout rate that echoed his best years with the Cardinals. Did he walk 12.5% of opposing batters? Sure, but you have to crack a few eggs to make an omelet, and he had been plenty effective in St. Louis even with slightly elevated walk rates. The Royals dealt him to San Diego in exchange for Edward Olivares and Dylan Coleman, two mid-level prospects, and everyone walked away happy.

Wait, hold up. Rosenthal has a career 2.75 FIP (and a 3.46 ERA and 3.32 xFIP, it’s hardly smoke and mirrors). He had a career 2.79 FIP before his solid 2020. He got flipped for two real prospects after 13 innings of relief work, after 233 pitches. Teams seemed to agree that he had value. Why did he have to take a minor league deal to prove himself?

Take a look at Rosenthal’s 2019, and you’ll understand why. The bullpen-needy Nationals signed him to a one-year deal after he skipped 2018 to rehab from Tommy John surgery. He made 12 appearances — and allowed 16 runs while walking 15 and striking out only five batters. It was bad enough that the Nationals — who at times used a cardboard cutout of Rollie Fingers as a closer — simply released him. The Tigers gave him a shot — and released him again after he walked 11 in 10 appearances. The Yankees gave him a minor league deal, but that lasted all of one appearance, which featured three walks out of five batters faced. It sure looked like the end of the line.

In that nightmare year, Rosenthal’s problem was obvious: he couldn’t throw strikes. Only 44% of his pitches were in the strike zone, as compared to a league average of 48%. Even worse, he didn’t miss close. Batters chased only 19% of his pitches outside the strike zone (29% is average). When he got behind batters, he hit the zone less. Only 43% of the time (55% is average). Because of that, batters swung less; he got into more 45 1-0 counts out of the 85 batters he faced, a bottom-10 rate. There are only so many ways to say it: he was unplayably wild.

More specifically, his fastball was unplayably wild. Once his marquee pitch, he couldn’t get it anywhere near the strike zone. His 41.1% zone rate on the pitch was the fifth-worst among pitchers who threw 250 fastballs in 2019. The others were less fastball-reliant; Rosenthal threw 72% fastballs that year, and he’s at 76.3% for his career. Rosenthal without a fastball won’t work.

The good news? It’s easy to tell when someone can locate their fastball again. With Kansas City, he hit the zone 53% of the time with his fastball. After moving to San Diego, he held it constant at 53.4%. That’s back to where he was in St. Louis, and it’s pretty easy to spin yourself a story: Rosenthal needed a year to recover from TJ, didn’t get it, and simply wasn’t ready in 2019.

That doesn’t mean he’s suddenly without risk. But he was one of the best relievers in the game before blowing out his elbow in 2017. He’d posted four seasons with a sub-3 FIP in his first five years. He repeated that in 2020 and also set a new career high with a 41.8% strikeout rate. It was no fluke; he had a career-high swinging strike rate driven by his new slider, which generated whiffs 40% of the time he threw it.

This form of Rosenthal, the version where he locates his 98 mph fastball and plays off of it with a lethal changeup and new slider, is a relief ace. Ignore the projections, which call for ERA’s and FIP’s in the fours. If he’s back, you should expect something with a two or three in front of it. That’s a fine arm to slot in as closer. The A’s have plenty of solid relievers, but Rosenthal is the capstone to replace Liam Hendriks.

Of course, that’s if he’s right. If you think forecasting is hard, try forecasting the future for a player who went from unhittable to unplayable to unhittable, with injury risk thrown in for good measure. That’s why Rosenthal’s projection looks so weird; it’s trying to turn a binary (2019 or 2020) into a point forecast, and that’s hard to do. This doesn’t feel like a thing that can be halfway — he’s not likely to alternate between finding the zone exactly and having no idea where the ball is going.

What would you pay for a reliever who will either be a borderline All-Star or unplayable? Eleven million dollars isn’t an unreasonable number for that. If you think Rosenthal’s peak form is worth $14 million per year — somewhere in between what Hendriks got in Chicago and what Will Smith got last year in Atlanta — he needs to be Good Trevor 80% of the time to make the deal work.

That’s not how real life works. There are ranges in between. He might be healthy but ineffective, or lose two ticks of velocity but retain his feel for the strike zone. Maybe his slider will lose some bite, forcing him to re-integrate his changeup, which seems to have benefited from sparing use. Almost no one is truly either elite or garbage, no matter how much I try to tell you so in an article.

If you’ll grant me that Rosenthal is at least uniquely boom-bust, this deal starts to make more sense. With only one year of recovery under his belt, Rosenthal’s true talent is as uncertain as it’s going to be. If some team signed him for four years, only to see him turn into a pumpkin immediately, that’s a terrible outcome for the team. This isn’t like signing some slugger to a deal that pays him $15 million per year and having him be worth only $10 million per. If Rosenthal is bad, there’s a decent chance he’s a complete zero. That’s why multi-year offers for Rosenthal were significantly lower — the downside risk of those extra years is higher given his profile.

If he’s good this year, the risk of complete meltdown decreases significantly. He’s 23.2 innings removed from being literally the worst pitcher in baseball. If he throws a full workload this year, he’ll quadruple his sample of post-TJ effectiveness. All of the sudden, a multi-year deal doesn’t feel quite so boom/bust.

What decision would you make, were you in Rosenthal’s shoes? He’s earned roughly $22 million in his career, enough to live comfortably, but before his UCL tear, he could imagine far more. He’d be making star closer money if things hadn’t gone wrong. He’s already 31, without too many more years to cash in. Every extra year of a middling-AAV contract is one fewer year to get what could have, and perhaps even should have, been his.

I’ve never spoken to Trevor Rosenthal, so this is all speculation, but it’s hardly a leap of faith to assume a professional athlete is confident in his own abilities. For the A’s, their motivation requires even less unpacking. The team has, in recent years, been built to get the most out of a middling rotation. They’ve done that with a beastly bullpen. The last time they finished outside the top 10 in WAR, ERA, or K-BB% was 2017, not coincidentally the last year they missed the playoffs.

After this week’s addition of Yusmeiro Petit and Sergio Romo, the A’s have a reasonably deep ‘pen. By adding Rosenthal, they’re increasing the ceiling; if he repeats his 2020 form, he can be a facsimile of Hendriks, providing the high-leverage juice to complement the inning-eating competence they already possess.

If he doesn’t work out — well, yeah, that’s no good. For a team that cries poor to such great extent, hitting on every deal seems important. The A’s total payroll will check in around $85 million this year, and they’re counting on Tony Kemp, Stephen Piscotty, Chad Pinder, Ka’ai Tom, Vimael Machín, Jed Lowrie, and Aramis Garcia to provide nearly 2,000 plate appearances, per our Depth Charts projections. That’s a pretty wide swath of mediocrity, particularly given what mid-tier bats are going for on the open market these days.

If Rosenthal works out, I get it. Spending that money to turn your bullpen into a weapon might let you leverage the team in new ways. Planning on winning every one-run game actually sounds like an easier way to make the playoffs than trying to slug it out position-by-position against the teams with Alex Bregman and Mike Trout.

Bake in the risk of ruin, however, and I’m skeptical that this makes sense. The fail case of signing a passel of mid-tier hitters is that you don’t improve the team enough to compete with the rest of the division. It’s possible, and in a top-heavier division it might even be a good idea. But the A’s look competitive, even with the obvious holes in their lineup. They seem aware of this — they signed Mitch Moreland this week, and they’re generally behaving like a team in need of reinforcements. Against that backdrop, I think I’d rather try to catch lightning in a bottle with a cheaper reliever and spend the balance on improvements elsewhere.

None of this is to say that Rosenthal isn’t worth his $11 million contract. In fact, I think that Rosenthal is likely to deliver more than $11 million of value. Maybe I’m crazy, but I can’t see why Oakland is the one employing him, instead of a team with harder-to-fix holes elsewhere. It’s a logical contract for an exciting player — but one that doesn’t seem to fit the team that wrote it.