Diamondbacks listening to trade offers on LHPs Andrew Chafin, Joe Mantiply

The Diamondbacks made a big addition to their bullpen yesterday when they acquired Paul Sewald from the Mariners. It seems they have at least some openness to now subtracting from their relief corps, as Ken Rosenthal of The Athletic reports they have fielded offers for lefties Andrew Chafin and Joe Mantiply, with the Brewers listed as a team with interest in Chafin.

On the surface, it’s a little bit curious to see the Diamondbacks considering this path, as they just parted with infielder Josh Rojas, rookie outfielder Dominic Canzone and infield prospect Ryan Bliss in order to upgrade their bullpen with Sewald. They are currently tied with two other clubs for the final Wild Card spot in the National League. To now turn and remove pieces from the group would be a bit of an odd move, though listening to offers doesn’t necessarily mean the club will indeed make a move, as front offices are generally open to listening to all offers in order to gauge the market.

Chafin, 33, has long been one of the better lefty relievers in the league, with a 3.31 career earned run average over 519 appearances. Over 2021 and 2022, he made 135 of those appearances, posting a 2.29 ERA with a 25.7% strikeout rate, 7.5% walk rate and 47.9% ground ball rate. The Diamondbacks were able to bring him aboard on a one-year deal this offseason, guaranteeing him $6.25M in the form of a $5.5M salary plus a $750K buyout on a $7.25M club option. There’s also $1M in bonuses available, with Chafin getting $250K at 55, 60, 65 and 70 appearances, then another $250K bonus if he’s traded.

He has already made 43 appearances in the year, putting him close to triggering those bonuses. His 4.19 ERA in that time is obviously a drop-off from his recent work, though there are still some decent numbers under the hood. His 35.4% grounder rate and 12% walk rate are less than ideal, but his 32.7% strikeout rate is easily a career best. A .350 batting average on balls in play has probably helped some extra runs across the board, leading to a 3.13 FIP and 3.38 SIERA.

Left-handed relief is always in demand and there would likely be plenty of clubs willing to look past Chafin’s ERA, especially given his long track record of success and intriguing strikeout bump. Rosenthal says the Diamondbacks are still looking for starting pitching, something that general manager Mike Hazen has long been open about. They might not be able to flip a reliever like Chafin for meaningful help in the rotation but it makes sense that they would at least listen to see what’s possible.

Arizona listening on Mantiply is far easier to understand. He had a really solid showing in the previous two seasons, posting a combined 3.07 ERA in 2021 and 2022, getting selected to the All-Star game in the latter season. He struck out 23.6% of opponents in that time while walking just 5.5% and kept the ball on the ground at a 50.5% pace.

Unfortunately, he wasn’t able to carry that into 2023, as he has a 5.74 ERA in 15 2/3 innings. He’s been on the injured list twice, once due to left shoulder inflammation and then a right hamstring strain. He’s been sent to Triple-A Reno on optional assignment twice, the second of which is currently ongoing. He has a 7.30 ERA down at that level. But his rate stats are still decent this year, with poor strand rates and some extra fly balls leaving the yard perhaps making things look worse than they actually are. If any club is willing to bank on Mantiply’s past results and hope for a bounceback, it would make sense for the Diamondbacks to hear that out since he’s not even on their active roster at the moment.

The Brewers have operated with one lefty, Hoby Milner, for most of the year. They had Justin Wilson come off the injured list this week after over a year rehabbing from Tommy John surgery, but he quickly landed right back on the IL due to a lat strain. They’re a fairly sensible landing spot for a southpaw reliever as they battle for the Central Division title or a wild-card spot in the National League.