The Cubs will call up lefty Justin Steele and insert him into their starting rotation for the upcoming series against the Brewers, sources confirmed to NBC Sports Chicago.
The Cubs will go with a six-man rotation once Steele joins the group.
Steele has been stretching out as a starter with Triple-A Iowa for the last month. In five starts, he has a 0.87 ERA and 0.97 WHIP, striking out 27 (nine walks) in 20 2/3 innings.
Steele started for Iowa Wednesday, so Monday would be his natural fifth day. He threw 80 pitches in that start, allowing one run in five innings.
The next two months will allow the Cubs to see what they have in Steele and other young pitchers, including Adbert Alzolay and Keegan Thompson, as they try and determine their competitive timeline as soon as possible.
Alzolay pitched well in his latest start, allowing two runs in 6 2/3 innings Saturday vs. the White Sox, and was looking forward to the possibility of Steele joining him in the Cubs rotation.
"We were pitching in the same rotation for years [in the minor leagues]," Alzolay said. "It's going to be special having one of my best friends next to me in the rotation at any time, hopefully sooner than later."
Steele made 11 relief appearances with the Cubs earlier this season before going on the IL with a hamstring strain. He has a 2.03 ERA in 11 appearances.