One Worrisome Stat For A's Newcomer Mark Leiter Jr.
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The A's have been after a veteran bullpen arm this offseason, and earlier this week they landed one in 34-year-old right-hander Mark Leiter Jr., who had spent the past two seasons with the New York Yankees.
On the surface, his numbers weren't great with the Yankees last season. He held a 4.84 ERA with a 1.53 WHIP. That said, looking a little closer at his stats, we've noted that the expected numbers thought a lot more highly of him, given that he limited hard contact, kept the ball on the ground at a high rate and ran a .374 BABIP, suggesting some bad luck on balls in play.
Plus, in the first two months of the season, Leiter held a 2.28 ERA in his first 23 2/3 innings. On May 31 he was touched up for four runs against the Los Angeles Dodgers, and his season kind of went downhill from that point forward. From May 31 through the end of the season, Leiter's ERA skyrocketed to 7.30 (5.28 FIP) in 24 2/3 innings.
One worrisome stat for Leiter
There are some statistics that vary from year-to-year, meaning that it's difficult to put a lot of stock in them from one year to the next. BABIP is one of those. If a pitcher is running a high BABIP one year, the assumption is that it'll more or less even out the following year.
Another one of those numbers is typically the rate at which inherited runners end up scoring for relief pitchers. That said, Leiter has had an unfortunate knack for allowing inherited runners to cross home plate at a fairly high clip.
This past season, he was "gifted" 36 base runners. 15 of them came around to score, which is 41.67%. By comparison, Mason Miller allowed four of the 19 he inherited to score (21%). Obviously Miller and Leiter aren't necessarily comparable players, so here is how the A's projected bullpen fared in 2025.
Inherited | Scored | % | |
|---|---|---|---|
Harris | 30 | 9 | 30% |
Sterner | 27 | 8 | 29.6% |
Ferguson | 29 | 3 | 10.3% |
Alvarado | 6 | 2 | 33.3% |
Kelly | 15 | 1 | 6.7% |
This just gives you a sense of what the norm is for the A's current relief pitchers. As we said, just because a pitcher runs a high (or low) rate one year, that doesn't mean that the results will follow that trajectory the following year.
That said, Leiter's rates the past few years have been 25% (2024), 41.9% (2023) and 35.7% (2022) the past few years, so his inherited runners do tend to come home a decent amount of the time. In three of the last four seasons, he would have held the highest rate among A's relief pitchers, based on their 2025 data.
The simple fix
The easy way around this issue is to never give Leiter an appearance where he enters with runners on base, right? Of course, that's not exactly possible, given how fresh the bullpen is (or isn't), who can go on a certain day. Who comes in is often matchup-based as well. If Leiter's splitter could get a big double play to get the A's out of a big jam, are they not supposed to take that chance?
Leiter has the most saves of anyone in the A's bullpen with nine in his career, which is also nearly more than the rest of the A's relievers combined. Harris (4), Ferguson (4) and Kelly (2) have combined for 10 total saves in their careers. Still, he doesn't figure to be the full-time closer.
The way the roster is currently constructed, it would appear as though the A's are going with a closer by committee approach yet again in 2026. There is still plenty of off-season left for the green and gold to make a move, however, so we'll have to wait and see how everything shakes out.
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Jason has been covering the A’s at various sites for over a decade, and was the original host of the Locked on A’s podcast. He also covers the Stanford Cardinal as they attempt to rebuild numerous programs to prominence.
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