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Previewing Relief Pitching Options at the Trade Deadline

You can’t have enough good pitching

MLB: World Series-Houston Astros at Atlanta Braves
Relief pitcher Kendall Graveman, acquired in 2021 at the trade deadline, is shown here in Game 5 of the World Series that year.
KendaBrett Davis-USA TODAY Sports

With the trade deadline less than three weeks away, I will continue previewing potential trade targets. Last week, my article previewed starting pitchers. This article will preview potential relief pitcher targets.

Do the Astros need to fortify the team at the trade deadline? I would say, “Yes.” According to Fangraphs’ model, the Rangers and Astros are practically tied in terms of odds of winning the AL West. (44% Rangers, 42% Astros) Both teams will try to use mid-season trades to give themselves the edge in the divisional race. The Astros’ overall odds of making the playoffs are 65%; good odds, but not overwhelmingly comfortable, given the number of teams competing for the Wild Card.

A few weeks ago, Dana Brown said that his biggest need at the trade deadline would be a bat, preferably LHB. Last week Brown said he would be looking at all three types of players—hitters, starting pitching, and relief pitching—at the trade deadline. I wrote in last week’s article that starting pitching should be the priority, which is still my opinion. However, the case for acquiring a relief pitcher is almost equally persuasive.

Let’s take an overview of the current bullpen. The relief pitching is so good that your initial reaction may be to make it a low priority. The Astros’ bullpen is rated No. 1 in Stuff+, which means their stuff can overwhelm batters in the late innings. Relievers Ryan Pressly and Bryan Abreu are absolute Stuff+ monsters. The Astros’ bullpen ERA is No. 4, which is quite good. But ERA is not necessarily the best measure of reliever performance.

Moving on to peripheral measures indicates perhaps the beginning of storm clouds. RE24, a win probability stat, is a good metric for relief pitchers—better than WHIP. The Astros relievers rank 11th on RE24—good but not equal to the ERA ranking. The relievers are 11th in meltdowns, again good but not great. The Astros relievers are ranked 19th in shutdown innings, which is below average. Finally, the Astros’ bullpen ranks 5th in SIERA, which is a good sign for the future.

The real case for fortifying the bullpen is workload. The issue is whether the direction of future bullpen workload will cause fatigue and performance deterioration. The Astros’ bullpen usage is concentrated among a core of pitchers—Maton, Neris, Abreu, and Pressly.

Based on the trend in current innings pitched:

  • Ryan Pressly is on track to increase his 2022 innings by 25 IP, an increase of over 60%.
  • Phil Maton is on course to increase his 2022 workload by 22 IP, a 27% increase.
  • Bryan Abreu is on track to pitch 81 innings, which is 16 more than his 2022 workload, a 26% increase.
  • Hector Neris, tied for 2d in Astros’ 2022 workload, is on course to exceed that total by five innings.

If Rafael Montero’s performance returns to his 2022 form, that would partially alleviate the late-inning workload situation. But we don’t know if he will. Ryne Stanek is on track to repeat his 2022 workload, and so far, he has taken up some of the slack from Montero. But the bullpen workload situation could be aggravated by injuries and performance issues in the starting rotation. For instance, 3/5 of the rotation is composed of rookies, whose workload will need to be managed in the second half. If the starters cannot continue to pitch deeply into each game, this adds pressure to the bullpen’s workload.

Innings pitched in the bullpen are high-effort innings, with the stress of frequent runners on base. Moreover, relievers sometimes have to get up and down to warm up, even if they are unneeded in the game. During Saturday’s game, Fox analyst and hall of famer John Smoltz, who pitched as a starter and as a closer, said that, in his experience, 75 appearances in the bullpen are more stressful on the arm than 250 innings as a starter. He specifically mentioned the workload added by continually warming up in the bullpen.

It’s not clear if the Astros have to add a bullpen arm or not, particularly if Montero can return to his 2022 form. But this is a clear risk area for the remainder of the season. If the Astros could acquire a reliable bullpen arm capable of working high-leverage innings, this would reduce the workload pressure on the four core relief pitchers, who are on track to greatly exceed last year’s workload. In particular, the Astros must reduce the bullpen’s reliance on Bryan Abreu, who is headed for a likely unsustainable workload.

What is the trade cost? Obviously, it depends on the pitcher and the years of team control remaining. But former GM James Click did a remarkable job of re-vamping the bullpen in 2021 at a relatively low trade cost. During the 2021 mid-season, he added a late-inning reliever, Kendall Graveman; a future late-inning reliever, Rafael Montero; and middle relievers, Phil Maton and Yemi Garcia. Two of the acquisitions had future team control, and two were rentals. Graveman and Maton would become key contributors in the 2021 playoffs.


I used the same screening methodology that I applied in my article on starting pitcher trade candidates. My initial screen is based on a positive E-F, meaning that the player’s ERA is above the player’s FIP. (E-F is a column on the Advanced Pitching Stats Leaderboard at Fangraphs.)

This is a good screening test because it means the pitcher’s results reflect underperformance, which should reduce the trading cost. Furthermore, it suggests that the likelihood of regression will be in the direction of better performance in the future. Furthermore, my review is supplemented by reviewing x-ERA and SIERA, which may be more relevant to future performance. In addition, I have added Stuff+ to the evaluation because the pitcher’s pure stuff may be more important in late-inning relief work.

Beyond these criteria, I have subjectively selected starting pitcher trade targets based on the desirability of the pitcher and the likelihood that the player’s team will be sellers and might engage in a trade with the Astros.

Potential Trade Targets

(Note: I have previously addressed Kansas City Royals relief pitcher trade targets here. Carlos Hernandez and Scott Barlow are discussed in that article, and would meet the screening criteria in this article.)

A.J. Minter ERA 4.91 FIP 2.83 SIERA 2.88 x-ERA 3.58 Stuff+ 114

This is probably an unrealistic trade target. The Braves obviously are not sellers, and Minter, a LHP, has one more year of control. But this is a good example of a reliever with a bad ERA, but all signs pointing to probable excellent performance in the future. Given the ERA results, Minter is not used as the closer, but there is no indication that the Braves have given up on him. Minter’s Stuff+ is the best in the Atlanta bullpen, which shows why he would be an excellent acquisition who could take some of the workload off of Abreu.

Sam Moll ERA 5.01 FIP 3.40 SIERA 3.70 x-ERA 3.18 Stuff+ 87

This 31-year-old lefty reliever isn’t arb eligible until 2028. He has a high ERA, but most of the forward-looking measures indicate that he should carry a lower ERA. ZIPS and Staamer project his Rest of Season ERA at 3.73 and 3.45, respectively. Given his poor Stuff+ result, I suspect that Moll is better suited for middle relief rather than high-leverage relief. I’m not sure that Moll is an improvement over Seth Martinez. However, his 94.7 FB velocity is better than the softer throwing Martinez.

Dylan Floro ERA 4.37 FIP 2.85 SIERA 3.08 x-ERA 3.00 Stuff+ 103

The Marlins are in wild card contention, which means that a trade with Miami may not be realistic. The 32-year-old will be a free agent next year. Floro is a 93 mph groundball pitcher with a somewhat elevated ERA. But his forward-looking stats are all favorable. His Stuff+ metric is reasonably good, and the Marlins have used him to close out games on occasion (7 saves).

Angel Perdomo ERA 4.30 FIP 2.80 SIERA 3.08 x-ERA 2.75 Stuff+ 97

The tall (6-8) 29-year-old lefty reliever has only one year of service time. Pittsburgh may or may not be in contention at the trade deadline, so, it’s uncertain whether they would be willing to trade bullpen assets. Perdomo has only pitched 14 innings this year, but he has shown good strikeout ability. His somewhat elevated ERA in limited work belies relatively good forward-looking metrics.

Sean Manaea ERA 4.15 FIP 2.82 SIERA 2.84 x-ERA 4.95 Stuff+ 99

The 31-year-old lefty is well known to the Astros as a former member of the A’s rotation. He has one year remaining on his contract. He now pitches for the Giants, and it is unclear whether they will be buyers or sellers. Manaea is a swing reliever, and he could potentially contribute to solving Astros issues in both the bullpen and rotation. Manaea has pitched better out of the pen than the rotation, and all the numbers above, except x-ERA, result from his bullpen work. Other than x-ERA, which includes his less favorable starting stints, the forward-looking stats (SIERA and FIP) point to a good addition to the bullpen.

Chris Stratton ERA 4.20 FIP 2.99 SIERA 3.50 x-ERA 3.50 Stuff+ 108

Even though the Cardinals appear to have little hope for contending in the NL Central, it’s still very possible that the team will not sell at the deadline. But if they do, Chris Stratton meets the screening criteria. His ERA is somewhat high, but the metrics more aligned with future performance are relatively good.

Jordan Hicks ERA 3.93 FIP 3.12 SIERA 3.47 x-ERA 3.23 Stuff+ 129

I have already mentioned the uncertainty as to whether the Cardinals will be sellers. But the hard-throwing Hicks (101 avg. velocity) is an attractive target who will be a free agent next year. In addition to his high velocity, Hicks’ Stuff+ is close to elite status, and he would fit in well in the Abreu-type late-inning role. I wonder if Hicks’ brutal throwing error in the 9th inning, which cost the Cardinals an almost certain win, could be a reason to trade him. Hicks has been roasted by Cardinals fans for the blunder, which you can see here. Maybe he would be better off pitching far away from the fan reaction.

Julian Merryweather ERA 3.35 FIP 2.94 SIERA 3.65 x-ERA 2.07 Stuff+ 124

Merryweather is a hard-throwing (97.8 avg. velocity) 31-year-old RHP. Presumably, the Cubs will be sellers at the deadline. Merryweather will be arb eligible next year, and will be under team control through 2026. Possibly the Cubs will be reluctant to trade the reliever, preferring to take advantage of the remaining team control. Merryweather’s current ERA and his forward-looking metrics are both very good. Merryweather’s Stuff+ rating is excellent and would fit nicely in the high-leverage innings.