A nightmare scenario unfolded for the Chicago Cubs on a rainy Tuesday night in Pittsburgh.

Shota Imanaga was working on yet another gem against the Pirates, but the Cubs left-hander ultimately was forced out of the game after only one batter in the sixth inning with an apparent injury.

The next inning, the team revealed Imanaga had been removed with leg cramps.

“Both legs in the quad area were cramping,” manager Craig Counsell told reporters after the game. “It was kind of easy – had to take him out. He feels fine now – no issues. So hopefully it was just that.”

Imanaga said he felt something in the fifth inning that he described as a cramp forming and informed Cubs coaches.

“In the sixth inning, my legs completely cramped,” Imanaga told reporters through interpreter Edwin Stanberry. “Before, it turns into a cramp in different areas of the body that all connects. I think it was the right call to call it there.”

The southpaw is confident he will be able to take his next turn in the rotation.

“I don’t think there will be any issue for the next start,” Imanaga said. “I’ve had it in the past where I’ve had that feeling coming along and I kinda push past it and that affects me negatively. I feel like today, I was able to stop it a few steps before it would become a bigger issue.”

That’s a major sigh of relief for Cubs Nation, which still is reeling from the loss of co-ace Justin Steele (out for the season after undergoing elbow surgery).

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Imanaga gave up a double to Andrew McCutchen to begin the sixth inning, and a conference on the mound immediately ensued with Counsell, team trainers and Stanberry.

Nothing looked amiss on the final pitch Imanaga threw.

Cubs reliever Daniel Palencia came into the game and promptly walked the first batter before retiring the next three and escaping the jam.

Imanaga threw five shutout frames before departing, and he hasn’t allowed an earned run to the Pirates in 19 career innings. He has a 2.77 ERA on the season and once again has been the Cubs’ ace after a stellar rookie campaign in 2024.

A long-term injury to Imanaga would be a brutal gut-punch to this team, which is off to a strong 18-12 start.

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Veteran starters Jameson Taillon and Matthew Boyd have performed well to begin the year, and Colin Rea has given the team a boost since joining the rotation in the wake of Steele’s injury.

But the Cubs also are without Javier Assad — who aggravated his oblique injury last week — and young right-hander Ben Brown (6.04 ERA, 1.89 WHIP) has struggled to begin the season.

Jordan Wicks could be the next man up if the Cubs need another starter, but top prospect Cade Horton also is lurking in Triple-A, and he might force his way into Chicago’s rotation at some point this summer.