CHICAGO -- Part of the decision to introduce Justin Steele and Keegan Thompson to the big leagues this year as relievers was based on need. It was also a way to manage their innings on the front end of the season.

Steele and Thompson have shown they can hold their own in the Majors, but their future home might very well be in Chicago's rotation. Now, both will be in the process of getting stretched out as starters with Triple-A Iowa, with the goal of a rotation audition down the stretch.

"Those two guys have proved that they can get big outs late in the game," Cubs pitching coach Tommy Hottovy said. "And now, we're continuing to see them work two times through the order, try to get three times through the order. We're just going to keep building."

The Cubs optioned Thompson to Triple-A Iowa prior to Tuesday's game against the Reds. Steele, meanwhile, officially joined Iowa earlier this month following a rehab assignment for a right hamstring issue sustained in May.

• Cubs' injuries and roster moves

The 26-year-old Thompson -- a third-round pick in the 2017 MLB Draft -- logged a 2.21 ERA with 43 strikeouts against 22 walks in 40 2/3 innings (27 games) for the Cubs. Manager David Ross often utilized the rookie as a multi-inning option.

Steele, 26, who was selected in the fifth round of the 2014 Draft, spun a 2.03 ERA with 21 strikeouts in 13 1/3 innings for Chicago prior to the injury setback. This year at Triple-A, the lefty has a 1.56 ERA, including a 0.84 mark in his last three starts.

Hottovy said there were plenty of benefits to using Thompson and Steele in the Majors as bullpen arms this season. The pitching coach cited the ability to test the rookies in higher-leverage moments that they might not experience in the Minors.

"One-hundred percent," Hottovy said. "There's nothing like pitching in the eighth inning of a 1-1 game. So, being able to use these guys out of the bullpen and put them in situations they may not face in a start, it just gives them a lot more opportunity to be exposed to a lot more things."

Ross: no need to 'push' Báez
Cubs shortstop Javier Báez was a late scratch from Tuesday's starting lineup due to the bruised left heel that has ailed the shortstop since Sunday.

"It's just not something we want to push," Ross said.

Ross did not think Báez was going to be available on Monday, either, but the manager ultimately used him as a pinch-hitter with the game on the line. Báez delivered a walk-off single against Reds lefty Amir Garrett, setting off a wild scene at Wrigley Field.

Ross said he heard from Major League Baseball about Báez's antics on the field after the hit, noting that it was "possible" that a suspension could loom. That said, the manager shrugged off Báez's emotional reaction.

"I love energy," Ross said. "I think that's part of sports and what makes it special. So, I love the fact that there's a little bit of tension. I wouldn't say it's in my comfort zone, how I would do things. But I also don't mind it.

"It brings something different and, to be honest with you, two competitors getting after it and showing emotion, I think that emotion can be really good for our game as well."

Worth noting
Cubs starter Kyle Hendricks escaped with a no-decision on Monday night, extending his unbeaten streak to a career-high 14 starts. The righty has gone 10-0 with a 2.90 ERA in that stretch, dating back to May 16.

It is the longest streak by a Cubs starter since Jon Lester had a 14-game unbeaten run from July 9-Sept. 25, 2016. The last Cubs starter to have a longer streak was Jake Arrieta, who went 24 games from July 30, 2015-May 31, 2016.

Quotable
"Early in the year, we didn't know. We really didn't. The emergence of these guys being able to pitch out of the 'pen early in the year has allowed us to get a better view of where we are as an organization with some arms." -- Hottovy, on Steele and Thompson