3 Major Questions Surrounding D-backs' Rotation

The Arizona Diamondbacks' starting rotation is in a state of transition. After trading away Merrill Kelly, losing Corbin Burnes to injury and anticipating the departure of Zac Gallen this offseason, plenty of questions swirl.

The D-backs' starters struggled, nearly across the board for the first half of the 2025 season, but began to steadily improve in the second half.

There's no hiding from the fact that Arizona likely needs to add talent to some degree to the rotation. A potential return of Gallen or Kelly could be in play, though unlikely.

Ignoring those external arms, here are three questions surrounding Arizona's in-house, under-contract starters.

1: What Will a Corbin Burnes Return Look Like?

Burnes had a bit of a slow start to his season, but by the time he went down with an elbow injury requiring Tommy John Surgery, he'd lowered his D-backs ERA to 2.66, and had been stacking together ace-like performances.

Now, the question is twofold. When will Burnes come back, and what will he look like upon return?

Burnes himself has stated he's aiming for a return around the All-Star Break of 2026 — a somewhat-earlier target date than may have been expected. But even once healthy enough to pitch, it can take time for pitchers to look like their old selves — if they ever do.

Considering Burnes is an ace in more ways than simply stuff or velocity, it seems likely he'll be able to return to at least most of his former self, but that is not a guarantee, and he may not look like a top-end starter right away, or even for the duration of the 2026 season.

If he does cone back strong, that raises another question. Will he take the two-year opt-out present in his six-year deal, or choose to play out the remaining four seasons in his home state?

2: What do Diamondbacks Do With Eduardo Rodriguez?

Eduardo Rodriguez has now posted an ERA above 5.00 in back-to-back years after signing a four-year, $45 million contract with the D-backs after the 2023 season.

Granted, he's been beset by injuries and some poor defense, but he's also displayed lowered command, and has simply not been effective.

Rodriguez's contract size could be a motivating factor in giving him a longer leash, but Arizona has also been known to cut ties with high-dollar veterans in the past (Madison Bumgarner in 2023).

A trade involving Rodriguez doesn't seem feasible without a significant salary committment by the D-backs, and a DFA seems unlikely with such little pitching depth behind him, but if Rodriguez's results continue to look poor, Arizona may be forced to make a touch decision.

3: Can Ryne Nelson Continue Sustained Success?

Every time Ryne Nelson touches the mound, the thought of "maybe this is the start that proves he's been figured out" creeps in. And yet, nearly every time, he proves that thought wrong.

Related Content: How Ryne Nelson Became Diamondbacks' Best 2025 Starter

Considering Nelson relies on his fastball to such a heavy extent, he does need to work his secondary pitches as effectively as possible, and teams did show an ability to key in on his fastball at times.

But said fastball is so effective, and his command of it was so good, Nelson was able to post an unbelievable +24 Run Value (per Statcast) on the pitch. Even with sub-par secondaries, that allowed him to maintain a 3.16 ERA over 128 innings as a starter (23 starts).

Depending on Arizona's potential offseason acquisitions, Nelson may need to take on a full-time ace role, and all the pressure and expectations that come with it. The 27-year-old does seem mentally and physically equipped to do so, but expectations of any one player or team are often inaccurate.

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