Have the Diamondbacks Figured Out Their Pitching Staff?

A combination of roster moves and good coaching has the D-backs pitching moving in the right direction

If one were to look at the year to date pitching numbers for the Diamondbacks staff they might reasonably conclude that the team ranks in the bottom third of MLB.  After all the year to date team ERA of 4.47 ranks 21st  and their team FIP of 4.38 ranks 19th.  Broken out by starter and reliever, the  SP ERA is 4.70 (19th) and RP ERA is 4.14 (18th). 

Hidden within those numbers however is a great deal of improvement. As the season has gone on the team has made a series of roster moves that have vastly improved the team's overall outlook and lowered the ERA. The net result is that over their last 20 games since May 8th, the team has a 3.72 ERA, which is the 7th best in MLB in that span. Most of the improvement appears to have come from the bullpen, who have a 2.85 ERA since May 8th, vs. the rotation 4.39 ERA.

Some of that improvement  came by moving on from or demoting pitchers that performed poorly.  They've done so relatively quickly.  Madison Bumgarner was DFA'd after only four starts.  Recent call up Brandon Pfaadt was optioned back to Reno after only five starts. For some of the other pitchers, they simply have pitched better of late. While Zac Gallen has stumbled a little bit in May, most of the rest of the staff has pitched better this month than last.  They have one of the best pitching coaches in MLB in Brent Strom, and he's clearly making a difference for some of them. 

Below is a look at just the pitchers on the current roster. (I include Joe Mantiply, who is on the IL but will likely return within a week). As you can see, these pitches have a composite ERA of 3.55, which is  nearly a run lower than the total team ERA  of 4.47.  They've also  accounted for 30 of the team's 31 wins.  Every reliever has an ERA+ over 100. 

Jack Sommers

Every team has pitchers that under perform or get hurt, causing them to cycle through their roster. It appears however that the Diamondbacks may have done a better job than most in this regard, finding the right combination of pitchers to go to war with for the next month or two as we head into the middle of the summer. Looking at the rest of season projections available at Fangraphs for just the pitchers in the chart above, I calculated a 4.08 ERA going forward. That's a half run higher than the year to date 3.55 ERA for this group, so it does suggest some regression.  Still, it's considerably better than the 4.47  team total year to date. 

Mike Hazen said during spring training that success in 2023 would be defined by being in a position to be buyers at the trade deadline and remain in the playoff hunt deep into the season. At the one third point through 54 games they stand at 31-23 and hold the top spot in the NL Wild Card race and are just 1.5 games back of the Dodgers in the NL West. 

If they've indeed found the right combination of pitchers we could very well see the Diamondbacks be aggressive in July and try to acquire more pitching for the stretch run and post season.  How that might play out and whether they target starting pitching or bullpen help, or both, remains to be seen. It's entirely unpredictable.  But these types of seasons and opportunities don't always come along, especially so soon after having a terrible season such as they had in 2021.  We documented the rarity of such a quick turnaround the other day.  Many Diamondbacks fans hope  the organization will seize the day.