PHILADELPHIA -- A Reds rotation already thinned by trades and injuries just received another unwanted setback. Rookie Graham Ashcraft, who has enjoyed a consistently strong season, went on the 15-day injured list Tuesday because of right biceps soreness.

Ashcraft returned to Cincinnati early from the Reds’ trip to undergo an MRI exam. Right-handed pitcher T.J. Zeuch was recalled from Triple-A Louisville and will start in Ashcraft’s place vs. the Phillies on Wednesday.

Manager David Bell was informed that Ashcraft felt the soreness during his side bullpen session on Monday.

“Not in a huge area of concern. Definitely looking to have him back quick,” Bell said. “We want him to continue the season he’s having and be able to finish strong. Certainly, enough there to kind of let it settle down and make sure he’s fine.”

Ashcraft, 24, made his big league debut in May and is 5-3 with a 3.97 ERA in 16 starts this season. He is well past his career-high innings total with 125 2/3 innings -- including 93 innings in the Majors. His previous high was 111 innings in the Minors last season.

Cincinnati was considering shutting down Ashcraft next month before the season ended. That might not need to happen.

“We were starting to take a really close look at that yesterday and then the biceps soreness came up when he was throwing,” Bell said. “It might just work itself out now.”

Without Ashcraft, the Reds rotation now consists of rookie Nick Lodolo, followed by Mike Minor, Justin Dunn, Luis Cessa and Zeuch.

Minor is 2-10 with a 6.44 ERA in 14 starts while Dunn is only three starts back from a 2021 shoulder injury (6.08 ERA). Cessa was moved into the rotation from the bullpen on Monday and pitched two innings in a 4-1 loss to the Phillies. Zeuch has given up 12 earned runs over eight innings in two starts and was optioned to Louisville on Saturday.

The Reds decided to use Cessa and Zeuch in the rotation rather than call up left-hander Brandon Williamson, who is ranked as the No. 6 prospect in the organization by MLB Pipeline.

Williamson, who was acquired with Dunn from the Mariners in March for Jesse Winker and Eugenio Suárez, has a 3.98 ERA in 22 starts for Double-A Chattanooga and Louisville. However, the 24-year-old has a 1.50 WHIP and has shown command issues with 63 walks in 104 2/3 innings.

“We’re all part of the organization, and I follow everything that is going on, but every player is on a different path, different timing for their readiness to be in the big leagues,” Bell said. “I think it’s just the decision of really liking where Williamson is, loving that we have him in the organization, but the timing of when he gets here, a lot of people are involved in that decision and want to do what’s best for that. Now is not the right timing, but it could be soon.”