The D-backs Must Rely on Young Starters to Carry Them Through

Injuries to Eduardo Rodriguez and Merrill Kelly create both risk and opportunity for Arizona

Apr 21, 2024; San Francisco, California, USA; Arizona Diamondbacks starting pitcher Slade Cecconi / John Hefti-USA TODAY Sports

Injuries are a major story across MLB and the Diamondbacks have had more than their fair share. Nowhere does this issue loom larger for Arizona than in the rotation, as they are without newly signed free agent Eduardo Rodriguez, and veteran mainstay Merrill Kelly.

Rodriguez is on the 60-Day IL with a shoulder strain (Lat) and is not eligible to return until May 25th. As of the latest updates he is still symptomatic and has not begun a throwing program.

Kelly also has a shoulder strain (Teres Major) and Torey Lovullo indicated that he's out for over one month as well. In the case of both pitchers, it's simply not known when they will return, but in a worst case scenario the team could be looking at not having either before the All Star break.

That leaves just Zac Gallen and Jordan Montgomery to front what was supposed to be a formidable, four deep rotation. Now the Diamondbacks must rely on a group of young starters to carry the load for 60% of the starts for at least the next couple of months. Those starters include Brandon Pfaadt, Tommy Henry, Ryne Nelson, and Slade Cecconi.

The table below shows the individual and collective performance of these four pitchers year to date. I've also downloaded all the starts made by pitchers age 26 and younger to create a comparison against the other young starters in the league. While the D-backs will hope for much better than the average, this helps present a reasonable expectation for pitchers of this age.

Diamondbacks Young Starters 2024 Year to Date / Jack Sommers

One key takeaway from the table above is that the D-backs young starters as a group have a FIP, or fielding independent pitching ERA of 4.00, which is much lower than their 4.67 ERA. FIP is based on strikeouts, walks and home runs allowed. The idea is that the random variance of what happens to balls in play (i.e. non homers) is stripped out allowing for a view of what the pitcher himself has more control over.

As a group the D-backs young starters give up more hits and homers, and strike out fewer batters than the average young starter, but they are also walking a third less batters, resulting in a strong 3.6 SO/W ratio. This is a positive sign for the maturation of this group.

Another positive sign is that the last three fill-in starts, two by Cecconi, and one by Tommy Henry have all been quality starts. Filling in for a late scratch Merrill Kelly, Cecconi went six innings giving up two runs in a win against the Giants on April 21st.

Last night Cecconi was even better, giving up one run in six innings to the Mariners and striking out eight in a tough luck loss. In between Henry pitched his best game of the year, going six innings and allowing just one run in a victory against the Cardinals April 23rd.

Adding to those developments, Ryne Nelson seemed to be turning things around before getting hit on the elbow by a line drive. In the 13 innings leading up to that injury he'd allowed just four runs, walked one and struck out 11. He is eligible to come off the injured list on May 4th.

Brandon Pfaadt has been up and down, and not yet pitched as well as what he showed during the Postseason last year. He's still struggling somewhat the second and third time through the order, although not nearly as badly as 2023.

The most encouraging sign with Pfaadt is that his FIP is over a run lower than his ERA. His .289 BABIP (Batting average on Balls in Play) is right around league average, but his sequencing in allowing hits and homers has been both poor and unlucky. If he can avoid location mistakes in key situations, a problem that has come up a lot so far, then his numbers should improve.

Once Nelson comes back the team will need to decide who to keep in the rotation from among these four starters. The odd man out could be optioned back to Triple-A Reno to remain stretched out, or possibly be sent to the bullpen to provide further coverage to reliever core that is also challenged by injury. (Paul Sewald, Miguel Castron, and Kyle Nelson are all on the injured list as well).

The D-backs have the 3rd worst record in the National League. They need to do more than just tread water over the coming weeks. They need to play above .500 and set themselves up for a second half run once they presumably get healthy. Getting consistent performance from this group of young starters will be critical in that effort.

There is also the potential benefit of more than one of these young pitchers establishing themselves as a bonafide, above average major league starter over the next couple of months. It should be noted that both Gallen and Kelly are free agents after 2025, and starting pitching is not a strength in the prospect pipeline behind these four pitchers.