Sergio Romo is so hot that he might be the A’s best reliever now

With the trade deadline approaching, the Oakland A’s could use some bullpen help. They never got a single pitch from their expected closer due to injury, and in the meantime three other arms have done almost all of the heavy lifting in the late innings.

Let’s consider what the A’s already have. Who has been their best reliever lately? Is it Lou Trivino, who should have been an All-Star? Or Jake Diekman, after last year’s breakout performance? Or the quietly effective Yusmeiro Petit? To find out, we need to invoke the classic Mystery Player game. Here are their stats going back two months to May 25, along with one more Mystery Player.

• Player A: 0.95 ERA, 19 ip, 23 Ks, 2 BB, 1 HR, 10 hits, 1.75 FIP, .215 xwOBA
• Player B: 0.78 ERA, 23 ip, 18 Ks, 9 BB, 1 HR, 14 hits, 3.34 FIP, .243 xwOBA
• Player C: 3.86 ERA, 23⅓, 6 Ks, 2 BB, 4 HR, 23 hits, 5.27 FIP, .343 xwOBA
• Player D: 3.24 ERA, 16⅔ ip, 20 Ks, 13 BB, 4 HR, 13 hits, 6.41 FIP, .380 xwOBA

And what if we take it back another month, to April 25? That’s almost the entire season. Same four pitchers, in the same order:

• Player A: 1.93 ERA, 28 ip, 33 Ks, 7 BB, 1 HR, 16 hits, 2.02 FIP, .219 xwOBA
• Player B: 2.18 ERA, 33 ip, 26 Ks, 17 BB, 1 HR, 25 hits, 3.62 FIP, .286 xwOBA
• Player C: 3.65 ERA, 37 ip, 17 Ks, 5 BB, 4 HR, 34 hits, 4.14 FIP, .306 xwOBA
• Player D: 3.29 ERA, 27⅓ ip, 37 Ks, 18 BB, 6 HR, 22 hits, 5.40 FIP, .349 xwOBA

Starting from the bottom, Player D is Diekman. He was an All-MLB Team finalist last year, but he’s beginning to get knocked around lately and it’s getting worse as time goes on. In his last 13 outings, he’s blown three of his seven save/hold chances, including allowing a couple clutch homers. Player C is Petit, who is also showing signs of wear after heavy use in the early season.

Player B is Trivino. His great stats should come as no surprise considering he was named AL Reliever of the Month for June. And yet, he still hasn’t been the most productive member of the A’s pen for about 80% of the summer.

Nope, that distinction goes to Player A, which is Sergio Romo.

That might come as a surprise to anybody who jumps to conclusions from small samples. Of course, Romo was awful for the first few weeks of this season, and got annihilated in his first seven appearances. But then he settled down for his next seven games, and I wrote this on May 11:

Sure, it’s only seven good games. But the April slump was only seven bad games, and before that he was good for 13 years. Which part feels like the outlier? ...

Romo’s ERA still stands at an ugly 7.30, because it takes a long time for a reliever’s stats to correct after such a thorough torching. His peripherals are ugly, because he really did get beaten in those early April games, he wasn’t just unlucky. But set that all aside and check it again in July.

It’s July now. He’s down to a 3.93 ERA, his 2.82 FIP is the best in the bullpen by a lot, and he leads the entire staff with a .262 xwOBA on Statcast.

Why the hiccup in April? Who knows and honestly who cares, as long as he wasn’t hurt, which he wasn’t and pretty much never is. A 38-year-old started slow (for only seven games!) after the weird pandemic year, and that itself is not weird. Sometimes good relievers suck for an entire year for no reason and then bounce back. This slump wasn’t even a month. It happens, and either it went away or he actively adjusted somehow to fix it.

Granted, one difference between Romo and his teammates is that he hasn’t worked the same level of high-leverage games, as he spent some time in middle relief getting back on track. But he’s gradually shifting back to a setup role, as in 11 of his last 13 outings he’s entered in either a save/hold chance (twice), a tie (once), or down by just one run (eight times, half of them with inherited runners on base). And it’s not like he doesn’t have late-inning experience to lean on, with more career history there than the rest of the entire bullpen combined.

He did blow one of those recent save chances, but only because he entered with the bases loaded and nobody out with a one-run lead and two All-Stars due up next (righty Adolis Garcia and lefty Joey Gallo) — literally the most difficult situation a reliever could face. He gave up one single (to Garcia) and otherwise got out of it cleanly, but that single was enough. That’s the only lead he’s blown all year, with six successful holds. He also blew one tie in April during his slump, during an insane 13-12 game where nobody pitched well.

Looking forward

So what do we do with this information? First, when we think of protecting a late lead, it no longer has to be a choice between Trivino, Diekman, or Petit, we can add Romo into the mix too — he might even leapfrog one of the others, the way things are going now. I wouldn’t go so far as to say Romo should be pushing Trivino for the closer spot, as seismic role-shifting isn’t always as simple as that, and anyway Lou is doing great in his own right so leave it alone.

But if a stray save chance came Romo’s way, like it has sometimes for Diekman and Petit? His slider still looks as impossible as ever, and he’s missing more bats than anybody on the staff except Diekman but with half of Diekman’s walk rate. Would you bet against him anymore?

There is one reservation I still have with Romo, though. He belongs in his own new inning, not trying to clean up somebody else’s jam. He’s been consistently bad at stranding inherited runners since 2016, with 42% scoring in over 100 opportunities (league average is usually in the low-30s percent). Even lately, while he’s been posting his 1.93 ERA and 2.02 FIP since late-April, he’s allowed 9-of-19 to score (47%).

There’s some logic to it, too. When you throw pretty much all sliders (well over half of Romo’s offerings), you’re going to get a ton of whiffs but you’re always going to hang one or two. You could make a similar criticism of any pitch perhaps, but my personal perception has always been that a slider-based arsenal has a bit more combustibility than the others, with the trade-off being that you can be an All-Star with just that one pitch if it’s good enough. Romo’s slider is as filthy as anybody’s, but opponents are still going to barrel up a single or even a dinger sometimes. Let’s get those out of the way with nobody on base, and leave the delicate escape jobs to Petit and Trivino. If you don’t believe me, then believe the numbers.

It might seem counterintuitive to not want one of your whiffiest relievers in there to strand runners by reducing batted-ball randomness, but when too many of those whiffs rely on sliders, empty bases might be the prudent path.

And finally, how should this affect what the A’s do over the next week before the trade deadline? Not at all, hopefully. One more in-house reliever finally stepping up doesn’t end their need for reinforcements, and if anything it just helps pick up slack for another now-struggling top reliever like Diekman or Petit. They would still be wise to add at least one more reliable late-inning arm, and maybe more.

But hey! One of last year’s free agents, who got off to a rough April, is looking great after all, in exactly the area where the A’s need the most help right now. How Sergendipitous!