Injury updates: Cubs activate Mark Leiter Jr. from IL, option Ethan Roberts

BALTIMORE – The wave of Cubs pitchers expected back from the injured list on either side of the All-Star break began to break Tuesday, as the team activated reliever Mark Leiter Jr. from the 15-day IL before opening a three-game series against the Orioles.

“Getting guys back healthy is a good thing,” manager Craig Counsell said. “It’s going to create more depth.”

In a corresponding move, the Cubs optioned right-hander Ethan Roberts to Triple-A Iowa. If all goes well, right-hander Javier Assad (right forearm extensor strain) could be next to return from the IL. Reliever Julian Merryweather (rib stress fracture) is on track to be activated shortly after the All-Star break.

“Mark’s going to have a pretty good role this series,” Counsell said. “It’s a left-handed heavy lineup on a night like tonight, and that suits his strengths.”

With Cubs right-handed starter Jameson Taillon on the mound, the Orioles started four left-handed hitters and two switch hitters, a group that includes the first four hitters in the Orioles lineup: Gunnar Henderson, Adley Rutschman, Anthony Santander and Ryan O’Hearn.

Against left-handed pitchers, switch hitters move to the right-handed batter’s box for matchup purposes. But Leiter, a right-handed pitcher who has been primarily used against left-handed pockets in high-leverage, has the advantage of forcing switch hitters to the left side.

He spent about two weeks on the IL with a strained right forearm and said it was “hard to say” how long he’d been dealing with the issue. With a high volume of innings, as the Cubs played the most one-run games in the league, his arm hadn’t been recovering the way he’d hoped.

In his last four appearances before landing on the IL, Leiter allowed eight runs in 3 ⅓ innings. In his previous 28 games, he’d only allowed nine runs for a 3.20 ERA.

In other pitching news ...

Assad, who reached his 15-day minimum on the IL Tuesday, threw a bullpen session in Baltimore.

“All reports are it’s been good,” Counsell said.

Right-hander Kyle Hendricks, who left his start Saturday with tightness in his lower back, played catch Tuesday.

“Feels way better than he did on his start day,” Counsell said.

Even after exiting, Hendricks said he was confident he’d be ready to start in St. Louis this coming weekend. He’s scheduled to throw a bullpen on Wednesday in Baltimore, which Counsell described as “the final check mark.”

Merryweather and Caleb Kilian (strained right shoulder) were both scheduled to appear in rehab outings Tuesday, with Triple-A Iowa and High-A South Bend respectively. It was Merryweather’s first rehab game and Kilian’s third.

PCA update

Cubs center fielder Pete Crow-Armstrong was “fully available” off the bench Tuesday, Counsell said. Crow-Armstrong hit in his pregame warmup Tuesday for the first time since getting stitches in his left thumb last Wednesday.

Crow-Armstrong's return to the lineup was slowed by swelling in his hand Friday, which prevented him from throwing.