D-backs Pitching Concerns Shift from Rotation to Bullpen

The D-backs' rotation had been a problem for most of the second half, suddenly now it's the bullpen that is struggling, possibly due to workload issues.

Sep 3, 2024; San Francisco, California, USA; Arizona Diamondbacks pitcher Justin Martinez (63) prepares to pitch against the Arizona Diamondbacks during the eighth inning at Oracle Park. Mandatory Credit: John Hefti-Imagn Images / John Hefti-Imagn Images

The Arizona Diamondbacks came out of the All-Star break the hottest team in baseball, going 26-8 from July 19th to August 25th. They've hit a bump in the road by going 4-6 over their last 10 games, however.

The D-backs had a bad 2-5 homestand, losing two of three to the New York Mets, and three of four to the Dodgers. They won two of three from the Giants in San Francisco this week, but dropped a disappointing series finale on Thursday.

The offense continues to score runs at an incredible rate. Leading all of MLB in runs scored for the season with 5.43 per game, they've actually scored 6.4 per game over their last 10. They've allowed 6.2 games over that same span however.

Since the All-Star break, the narrative with the pitching staff had been the rotation was struggling (with the exception of Ryne Nelson), but the bullpen was pitching very well, as a whole. Over their last seven games the script has flipped. Just as the rotation has begun to improve, the bullpen is in shambles.

D-backs Pitching Breakdown Since July 19th / Jack Sommers

From July 19th through August 29th, the starters struggled to a 4.65 ERA despite a respectable 3.78 FIP. The bullpen meanwhile was fantastic. The 3.20 ERA and 3.06 FIP were among the best two or three teams in the league over that span.

Now, just as the rotation has appeared to turn the corner, the bullpen has imploded over the last seven games against the Dodgers and the Giants. Clearly there has been some bad luck, as the relievers' FIP is less than half their ERA over this stretch. But even the 4.89 is inflated and cause for concern.

Are the relievers tiring, or was it just a bad week? That's hard to say of course. Only Torey Lovullo and his coaching staff, and the players themselves truly know. But there may be particular concern with high leverage relievers Justin Martinez, Kevin Ginkel, and Ryan Thompson. The below table shows the individual stats over the last seven team games since August 30th

D-backs relievers since August 30th / Jack Sommers

In Martinez's case, he's most likely been unlucky, as evidenced by the 2.52 FIP. He has converted all eight of his save chances, but had some hiccups in tied and extra inning games, leading to a several losses. The 23 year old Martinez has already surpassed his career high in innings pitched with 70 (majors and minor combined).

Ginkel was spectacular from the All-Star Break through August 29th, posting a 2.37 ERA and a microscopic 1.66 FIP. But pitching in four games in the last seven days on top of his previous workload seems to have caught up to him.

Ginkel has thrown 62.2 innings this year, compared to 65.2 regular season innings last year and 11.2 more in the Postseason. He went through some elbow soreness in early spring training, but recovered in time to be on the opening day roster.

Ryan Thompson has only pitched in two games this week, and struggled very badly in both. He had seen some inconsistency prior to that however, and things may have come to a head for him. Thompson has already long since surpassed his career high in innings. His 57.2 this year are 15 more than the 42.2 he threw in 2022.

Most curiously, A.J. Puk's workload has been very light. He's been the most effective reliever on the team of late, and really ever since he was acquired at the trade deadline. In 16 innings he has 26 strikeouts and a 0.56 ERA.

But Puk has an extensive injury history of his own, and Lovullo has been extremely protective of his workload, allowing him to face jut eight batters over the last week.

As mentioned above, the team may have some underlying concerns that they're not talking about. Martinez, Ginkel, and Thompson in particular probably need their workload lightened. If those concerns don't apply to Puk however, then look for the big left-hander's role and innings to increase in importance, at least while he's hot.

Perhaps this is what's really been on Lovullo's mind when he keeps insisting that the best version of the bullpen has Paul Sewald closing. The veteran's descent into ineffectiveness has forced the manager to lean heavily on the other high leverage relievers, and they appear to be wearing down.

It doesn't appear Sewald is going to retake the ninth inning closer's role any time soon however. The Diamondbacks will just have to hope that the current version of the bullpen can carry them to and through the Postseason.