ATLANTA -- A manageable rotation situation took a potentially darker turn on Tuesday for the Mets, who lost Taijuan Walker to back spasms after two innings of a 5-0 loss to the Braves at Truist Park. The issue occurred less than 24 hours after fellow rotation member Carlos Carrasco strained his left oblique, knocking him out for three to four weeks.

“It sucks, and the timing couldn’t be worse in something like this,” Walker said.

In the short term, Walker’s injury proved damaging when relievers R.J. Alvarez and Stephen Nogosek allowed five runs over 4 1/3 innings behind him, including homers to Robbie Grossman and Matt Olson. The loss trimmed New York’s division lead to 3 1/2 games.

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Longer term, Walker is due for an MRI on Wednesday, which will shed more light on his injury. (He’s unsure if he can make his next start.) Even if Walker’s issue doesn’t keep him out for long, the Mets’ rotten rotation luck has put their depth chart under a microscope at a critical juncture of their season. New York already planned to dip into those reserves this weekend, with sixth and seventh starters David Peterson and Trevor Williams scheduled to start both halves of a doubleheader in Philadelphia. What if another injury strikes?

Here’s how the Mets’ rotation depth looks with seven weeks left in the regular season:

(Note: These rankings are not official, but a rough estimate of where the following pitchers stand on the organizational hierarchy.)

No. 6 starter: LHP David Peterson
Key stats: 14 starts, four relief appearances, 3.30 ERA

So far, the Mets have resisted the temptation to convert Peterson to full-time relief work, despite Joely Rodríguez’s presence as the only left-hander in the bullpen. Knowing they would need a sixth starter on Saturday at a minimum, the Mets kept Peterson stretched out in the Minors so he could return to make that start.

Now, with Carrasco sidelined, the obvious move is for Peterson to remain in the rotation for the foreseeable future. That’s not a bad thing; as a starter, Peterson has been excellent, with a 5-2 record and a 3.17 ERA in 14 starts. He’s a key member of the club’s rotation depth for a reason.

No. 7 starter: RHP Trevor Williams
Key stats: Eight starts, 14 relief appearances, 20 consecutive scoreless innings, 3.02 ERA

It’s difficult to put Williams’ value to this staff into words. He’s been the glue guy all season, delivering everything from a two-out relief appearance back in April to a seven-inning scoreless start last month. If the Mets need Williams to start, he’ll start, and he’ll probably be pretty good at it.

“I’m thankful that [manager] Buck [Showalter] trusts me in this role,” Williams said. “I’m glad that I’m able to contribute, whether that’s starting or relieving or getting a random hold every once in a while, it’s fun.”

No. 8 starter: RHP Tylor Megill
Key stats: Nine starts, 41 1/3 innings, 47 strikeouts, 5.01 ERA

The Mets’ Opening Day starter, Megill has been sidelined since June 17 due to a right shoulder strain. He threw his first bullpen session on Sunday and could advance to rehab games by the end of the month, but the Mets’ plan is to convert Megill to relief work upon his return. That could of course change, but even if it does, Megill would need time to stretch all the way back out as a starter. He’s not a short-term option in the rotation.

No. 9 starter: LHP Joey Lucchesi
Key stats: Has not pitched since June 18, 2021

Mets officials have yet to reveal their intentions for Lucchesi upon his return from Tommy John surgery, which will likely happen in September. Lucchesi stands at least some chance of converting to relief work as well, considering the Mets’ lack of left-handed depth. But he could also stretch back out as a starting pitcher if that’s where the need is greatest. Lucchesi performed in both roles last year, producing a 1.19 ERA in his final five starts before tearing his elbow ligament.

Lucchesi has yet to begin a rehab assignment, but he’s already thrown multiple live BP sessions, which is typically the final step before Minor League games.

No. 10 starter: RHP Jose Butto
Key stats: 108 strikeouts in 92 1/3 innings at Double-A Binghamton

The Mets’ rotation at Triple-A Syracuse has been a revolving door, with 17 different pitchers starting games for the club. The most intriguing name in the rotation right now is Butto, the team’s 12th-ranked prospect who earned a promotion there last week. Best known for his changeup, Butto recently began throwing a slider to expand his repertoire. The four-pitch mix makes him an intriguing option for the Mets -- maybe not this season, but at some point in the medium-term future.

“Every start, every routine in the bullpen, I try to be better, better, better,” Butto said last week. “I feel really good now that I’ve got a new pitch.”