Stroman has a fractured right rib cage, with no timetable for a return

CHICAGO — The Cubs expected to have Marcus Stroman off the injured list and back on the mound at Wrigley Field on Wednesday night. That plan fell apart when the All-Star outfielder reported discomfort in his right side as the team left Toronto last weekend.

Now, the Cubs face an uncertain timeline for Stroman, who was diagnosed with a cartilage fracture in his right rib. Righty Javier Assad slotted into Stroman’s rotation slot Wednesday against the White Sox, and the North Siders will go into standby mode when it comes to the veteran’s latest comeback bid.

“I have no idea. That’s the honest truth,” Hoyer said. “We don’t really know at this point. Obviously, we’re going to give him a real rest period and see how he feels. But I want to say, again, I don’t it’s a real common pitching injury. I’ve never seen that before.”

Stroman has been in IL since Aug. 1 with right hip inflammation, but the righty worked three bullpen sessions on the team’s recent road trip to New York and Toronto with encouraging results. He completed a 50-pitch workout Friday and another light session Sunday, putting him on target to start Wednesday.

On Sunday morning in Toronto, Stroman told reporters he was “progressing to where I feel like I should be” and expressed excitement about leaving IL. By the end of the day, he informed the team that he was experiencing pain in his side, which led to an MRI exam on the team’s off-day Monday.

Both Hoyer and manager David Ross said it was unclear how the setback occurred. Stroman was not available for comment before Wednesday’s game against the White Sox.

“Disappointed, obviously,” Ross said. “We’ll just have to wait and see how long and how much it actually hurts. To bring him back, we’ll have to rely on him not having symptoms. So how long it lasts, no one really knows. So it’s kind of up in the air.”

Against the White Sox, Assad put together his second straight quality start, allowing three runs (two earned) in six innings for the North Siders. A lack of run support led to a no-decision for the righty, who posted a 1.38 ERA over his last 12 appearances for the Cubs.

“We are a better team when [Stroman’s] himself and out there for us,” Cubs second baseman Nico Hoerner said. “But we had a very admirable job from our staff paying him. And we will continue to do so.

“[Assad] he’s just a guy who I feel like isn’t really going to come across as much different one way or another – and I mean that in the best way. He was comfortable and confident with everything they gave him.”

Asad is likely to remain in the rotation for now, and the Cubs have solid depth at the top of the bullpen between Justin Steele, Jameson Taillon and Kyle Hendricks. Behind that group, lefty Drew Smyly and righty Hayden Wesneski offer a pair of options.

Both Smyly and Wesneski were in the Opening Day rotation, but recent struggles have led to respective bullpen moves. As things stand, Ross said he’s leaning toward giving Smyly the No. 5 rotation spot, which comes next Tuesday in Detroit.

“We have some depth,” Ross said. “Sometimes that gets tested and other guys have to step up when you want to go to the playoffs. Each group deals with small things that appear like this. We have a lot of professionals in this room. Lots of good grand champions. We’ll be fine.”

The 32-year-old Stroman posted a 2.28 ERA in his first 16 starts, which included a 7-0 streak with a 1.29 ERA in seven starts leading up to the London Series in late June. During that June 25 outing, a blister flared in the All-Star’s arm, leading to an early exit at the front end of a rough stretch (9.00 ERA in seven starts).

The Cubs were eager to get the first-half version of Stroman for the stretch run, but others have picked up the slack. Going back to June 25, the Cubs have a 24-19 record (entering Wednesday) and have climbed back into the National League Central and Wild Card races.

“Sure, we were hoping to get him back tonight,” Hoyer said, “and [for him to] started playing as it was in April and May. Obviously, that didn’t happen. But, we’ve been playing great baseball for quite some time now. I think at this time of year, you just deal with things like that and move on. We have depth.

“Obviously we’ve been using that depth for a while and we’ve been playing, so we’ve got to keep doing that. This time of year, you don’t stop and sink a lot. You say, “It’s too bad. We would like him to put us on film, but he is not. And we will continue to play well.”