CINCINNATI -- The Reds' rotation will undergo another revision later this week, manager Bryan Price revealed on Tuesday. Exactly how it will change is unclear, for now, but Luis Castillo will be moved out and Amir Garrett will be moving in. Tyler Mahle could also be shut down after a couple of more starts and Sal Romano might get pushed back a day or two.

"We have a general idea, but it's free-flowing," Price said. "I don't want to get too far into it because we haven't talked to all the guys. It's not a big deal. It's just reshuffling the deck."

Castillo will make his final start of 2017 against the Brewers on Wednesday. Since being promoted directly from Double-A Pensacola to the Major Leagues on June 23, the 24-year-old right-hander is 2-7 with a 3.32 ERA in 14 starts.

"I feel really happy with the job that I have done," Castillo said, via translator Julio Morillo.

The Reds are happy with the job, as well, but Castillo enters Wednesday with 161 2/3 innings pitched after he worked 131 2/3 innings in 2016 at the Class A Advanced and Double-A levels in the Marlins' organization.

Garrett, who is one of four September callups that arrived on Tuesday from Triple-A Louisville, will pitch one of the upcoming games in the next series vs. the Mets. Also called up were fellow starters Rookie Davis , Cody Reed and Jackson Stephens .

• Reds recall four pitchers from Triple-A

Reed is expected to go into the bullpen, a role he had when the season opened.

"There's a good chance you can see three of the four guys in the rotation at some point," Price said. "How many starts we can get them, I don't know. I can't make a great commitment until we actually get them slotted in. When we get Castillo out and Mahle out, it will become a little bit clearer."

Romano suffered a minor cut on his right index finger during his Sunday start at Pittsburgh and might be given extra rest. He's currently scheduled to pitch on Friday vs. the Mets. Mahle, who has made two big league starts since his Aug. 27 callup from Louisville, is slated to start on Thursday at New York. He has 155 1/3 innings pitched after he had 150 2/3 innings in 2016.

The Reds have used 15 different starting pitchers this season -- including all four of the September callups during their previous stints. Regardless of who makes the starts over the final 3 1/2 weeks, the only non-rookie who will get starts is veteran Homer Bailey. For the other pitchers, it's a chance to get an inside track for the 2018 rotation.

"This is a great time to finish strong," Price said. "We want all of these young guys we brought up from Triple-A and the kids we incorporated on to the team in the second half to really have a road map leading into Spring Training next year."

Worth noting:

Reds reliever Wandy Peralta underwent an MRI on Monday because of pain in his right hip that forced him out of a Sunday relief appearance vs. the Pirates. The tests were negative for a serious injury. Peralta could be cleared to resume playing catch on Wednesday.