Can the D-backs Survive their Devastating Rotation Injuries?

Eduardo Rodriguez and Merrill Kelly are making slower than expected progress. Zac Gallen's time table is unclear. In their absence, young Diamondbacks starters will need to fill the gap effectively to keep the team in the Wild Card hunt.

Arizona Diamondbacks pitcher Eduardo Rodriguez during spring training workouts at Salt River Fields at Talking Stick in Scottsdale on Feb. 14, 2024. / Rob Schumacher/The Republic / USA TODAY

The Diamondbacks have dealt with injuries in their starting rotation since the beginning of the season. Eduardo Rodriguez has not pitched at all this year, Merrill Kelly has only thrown 24 innings, and Zac Gallen recently went to the injured list with a hamstring strain.

Now we have learned that the timelines for them to return are trending later than first thought.

Eduardo Rodriguez is questionable to return before the July 15th All-Star Break. Rodriguez first suffered a left shoulder strain in his lat muscle late in spring training. He tried to begin a throwing program less than 10 days later, but suffered a setback in early April and had to be shut down again. He ended up on the 60-Day IL.

Rodriguez began a throwing program on May 10th, throwing from distances of 45 and then 60 feet. That has since been stretched out to 90 feet. Torey Lovullo declined to say exactly when Rodriguez might throw off a mound for the first time.

"I think the progression is 90, 105, 120, flat ground, and then get on a mound and throw a bullpen. He's going to continue to get evaluated, he's going to get imaging, we've got to make sure that we hit these landmarks and everything is showing up the right way before we take those next steps."

Merrill Kelly went to the injured list with a right shoulder strain on April 23rd, and later was transferred to the 60-Day IL. He recently underwent re-imaging on the shoulder that showed "significant healing" according to Lovullo. He will begin a throwing progression on Tuesday.

Lovullo often says the recovery time is "one to one, what they missed on the front side he's got to build up on the back." In Kelly's case, that math adds up to at least 40 days from now, so also around the All-Star Break or later.

Zac Gallen is not eligible to return from the injured list until June 15th. He will also start a throwing program tomorrow. Asked how confident he was Gallen would return on that date Lovullo declined to speculate. When Gallen had a similar injury in 2021, he was out the minimum of 15 days. This is a Grade-1 strain, the least severe.

"I don't know. I'm hoping it's going to be as short as possible... we've just got to be careful"

In the absence of these three starters the rotation is being filled with high priced free agent Jordan Montgomery and a group of four young pitchers, including Brandon Pfaadt, Ryne Nelson, Slade Cecconi, and Blake Walston. Two days ago I wrote about those four starters and the need for them to step up and mature into reliable options.

Pfaadt has done that this season, continually getting to or past the 6th inning and keeping games close. There have been encouraging outings from Cecconi, Walston and Nelson. They will need to continue to build consistency however, and do so for the next 6-8 weeks if the D-backs are to stay in the Wild Card race.

Left unsaid, because it is completely unknowable, is just how good Rodriguez and Kelly will be when they return. Shoulder injuries that are serious enough to keep pitchers out this long are potentially more likely to result in lowered effectiveness.

Gallen should not experience any effectiveness drop-off, as his hamstring injury does not affect his ability to throw the ball when he is able to pitch. He can either pitch or he cannot.

The team had the stated goal of limiting his innings after a career high 244 in 2023, including the postseason. So far this year he's thrown just 58 IP. While not how they wanted to have that happen, this could actually provide benefits down the stretch.

At this point, the Diamondbacks playoff hopes depend far more on their young starters than originally planned. Montgomery has not been the pitcher they paid $25 million for, posting a 5.48 ERA in eight starts. Furthermore, getting effective versions of Rodriguez and Kelly back sometime after the All-Star break should be considered a bonus.

A glass half full approach here is these young starters are going through trial by fire. If they, and the team, emerge from the next six weeks still in the pennant race, it will be because that long sought after pitching development has finally come to fruition with good results.