MILWAUKEE -- The Reds placed starting right-hander Tyler Mahle on the 10-day injured list on Monday because of a left hamstring strain. The move is retroactive to Saturday, the day after Mahle pitched against the Cardinals.

Mahle felt something in his hamstring on his final pitch in the sixth inning, and limped off the field during Friday’s 12-11 loss to St. Louis. Lucas Sims will start on Wednesday in Mahle’s place. The Reds recalled right-handed pitcher Sal Romano from Triple-A to move into Sims’ bullpen spot.

After being recalled from Louisville on Thursday, Sims pitched 2 1/3 scoreless innings of relief with one hit over two appearances for the Reds. Sims previously was up for one big league start on May 28, and pitched 7 1/3 innings with four earned runs allowed during an 11-6 win over the Pirates.

Romano returns feeling good

Romano came into Spring Training aiming to make the Reds rotation, and was disappointed when he didn’t make the team at all. Used most of the season in Louisville’s bullpen, Romano struggled with a 5.83 ERA in 32 relief appearances. But he thrived once he was moved into the rotation, and is 2-0 with a 1.59 ERA over his last four games (three starts).

“It kind of got me back into my routine, and figuring out myself mechanically and mentally, and really taking those couple of days between starts to work on my mechanics and realize that I’ve got to figure something out here,” Romano said of starting. “[Louisville pitching coach] Jeff Fassero did an unbelievable job of helping me down there tweaking a few things that needed to be done.

“My teammates had my back and were always telling me, ‘Sal, it’s going to come. You’re going to figure it out.’ They always kept believing in me. I thank them a lot for that, for sure. It helped me stay grounded, and that at some point this year, it was going to come.”

In 55 big league games, including 41 starts for the Reds over parts of the previous two seasons, Romano has had checkered results while going 13-19 with a 4.99 ERA. This year under Fassero at Louisvlle, he’s augmented his repertoire beyond his sinker and slider. Romano added a split-fingered fastball and improved his curveball.

"When you come up to the big leagues guys are going to hit mistakes. I've seen it live in the last two years,” Romano said. "I'm in a very good mindset right now. I'm very happy with where I'm at on all parts of my game. I'm happy to be here with these guys. I missed them all year. I'm happy to be able to come here in contribute, hopefully in a positive way."

Reds manager David Bell felt there was some concern over Romano’s struggles this year, but that the organization has maintained faith in him.

“We didn’t doubt that he would get back,” Bell said. “Maybe going into the rotation had something to do with it mentally. But you can either pitch and have the stuff to do it … but confidence and mentality and all of that plays into it. We have to make sure he believes in himself no matter what role he is going to be used out of here, and he will.”

Barnhart nearing rehab assignment

Injured Reds catcher Tucker Barnhart, who has been on the IL since June 28 with a right oblique strain, joined the club for the road series at Miller Park and took early and regular batting practice.

Barnhart is expected to head out on a rehab assignment with Louisville on Thursday. He started doing on-field work late last week at Great American Ball Park. All of the results have been positive, including when the switch-hitter swings from the left side of the plate.

“When I did it, I did it on a left-handed swing on my follow-through,” Barnhart said. “We’ve been working toward not feeling anything and we’re there. All the catching stuff has been fine. Swinging right-handed has been fine, a lot sooner than the left-handed side was. Now we’re at a point where I don’t feel anything. I feel like it’s a good time to get out and get back here as quick as I can.”

The Reds have also been without their other catchers -- Curt Casali and Kyle Farmer -- since last week because of injuries. Juan Graterol was called up from Louisville, and the Reds signed Ryan Lavarnway to fill in.

Prospects on the move

Cincinnati’s last two first round selections in the MLB Draft are moving up through the system. The fifth overall pick from 2018, third baseman Jonathan India, was promoted from Class A Advanced Daytona to Double-A Chattanooga on Monday.

This year’s No. 7 pick, left-handed pitcher Nick Lodolo, has been promoted to Class A Dayton from rookie-level Billings.

India, 22, is ranked by MLB Pipeline as the No. 3 prospect in the Reds’ system and No. 41 overall. With Daytona, he batted .256/.346/.410 with eight home runs and 30 RBIs in 87 games.

Lodolo, 21, posted a 2.38 ERA at Billings with three earned runs, 12 hits, no walks and 21 strikeouts over 11 1/3 innings. He is scheduled to debut and start for Dayton on Thursday.