In just his second start back from the IL, Jameson Taillon was rolling right along on Sunday.

Through five innings, he had thrown just 62 pitches and allowed only three hits. The only damage on the scoreboard came in the form of a solo home run from Los Angeles Angels slugger Taylor Ward in the first inning.

[Cubs takeaways: What we learned in win, sweep of Los Angeles Angels]

But Taillon didn’t come back out for the sixth. In his place stood reliever Andrew Kittredge, even though it seemed Taillon had at least a few more innings in him.

After the Cubs’ 4-3 win, manager Craig Counsell revealed the cause of Taillon’s early exit.

“He had a little groin tightness — left groin tightness — so it was kind of precautionary,” Counsell told reporters at Angel Stadium. “That was why I took him out.”

Prior to knowing the cause, fans were perplexed by the decision, especially after Kittredge allowed two runs in that sixth inning. It couldn’t have been workload-related, because Taillon threw 92 pitches on Aug. 19 in his return from the IL with a calf strain.

Instead, it was an injury scare for Taillon that surfaced as he was getting ready to head back out for the sixth.

[READ: How Kyle Hendricks fared in first start vs. former Cubs teammates]

“Just warming up for that last inning, I felt a little crampy sensation in my left groin,” Taillon told reporters after the game. “Hopefully, we caught it kind of early — hard to really tell this close to the game. I’m curious how (it will feel) when I wake up tomorrow and going forward.”

The Cubs will hope Taillon will make a recovery for his next start, because losing him for an extended period will mean yet another blow to a rotation that can’t seem to get healthy all at the same time.

Justin Steele has been out for the season since mid-April. Shota Imanaga missed significant time in May and June with a hamstring injury. Javier Assad only just made his first appearances of the season after dealing with an oblique strain, and the Cubs lost deadline acquisition Michael Soroka to a shoulder strain after two innings on his Aug. 4 debut.

Taillon threw only eight pitches in a quick bottom of the fifth, but a 26-pitch sixth inning for Angels reliever Chase Silseth meant Taillon was sitting for a while.

“It was a long sit. I went out there to kind of step on the warmup pitches and really get going and get the body moving again,” Taillon told reporters. “I just felt a tiny little cramp. I’ve dealt with something similar, and this feels (like) way less, so I’m encouraged.

“I pitched that whole fifth inning feeling a little something, so, if it was really bad, I wouldn’t have been able to do that.”

Should Taillon make a full recovery, his next start would likely fall at Coors Field against the Colorado Rockies next weekend.