CHICAGO — The next two weeks will be a true test of the Chicago Cubs’ mettle.

This is a team that sped out to a 21-13 start to the 2025 season before Shota Imanaga came up limping late in Sunday afternoon’s loss to the Milwaukee Brewers.

Imanaga was placed on the 15-day IL with a left hamstring strain Monday afternoon and the Cubs will now have to find a way to navigate at least the next two weeks without their ace. The team is also without Justin Steele, who underwent season-ending elbow surgery in mid-April.

It is something of a nightmare scenario for the Cubs, but they always knew this was a possibility. Pitching injuries are prevalent in the sport and teams set about building depth for situations just like this one.

“This is the nature of our game,” Cubs president of baseball operations Jed Hoyer said Monday afternoon at Wrigley Field. “You’re always building depth and you’re always dealing with injuries. You hope it’s not one of your best players, best pitchers. But that’s what happens.

“Hopefully we can figure out when we can get him back healthy. But we just got to step up. No one’s going to pause for us.”

As Hoyer said, the rest of the league doesn’t care that the Cubs are without their top two starting pitchers.

The timing certainly isn’t ideal with the Cubs slated to face off against a playoff contender in the New York Mets this weekend, but the schedule lightens up after that. The Cubs play the Marlins, White Sox and Rockies — three of the worst teams in the league — later this month.

The Cubs don’t know what kind of timeline they’re looking at with Imanaga’s injury but they do know they need players to step up and fill the void.

When Steele went down, veteran Colin Rea slid from the bullpen into the rotation and has been incredible (2-0, 1.86 ERA in four starts).

That was a relatively simple move for the Cubs to replace Steele. Rea was signed this offseason after making 49 starts for the Brewers over the last two years and was expected to make starts at some point this year, even though he began in the bullpen.

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The answers are not that simple this time around for the Cubs — even if fans have an idea of who they want to slot in the rotation.

Top pitching prospect Cade Horton is certainly an option, though the team was reticent to simply announce the 23-year-old right-hander as Saturday’s scheduled starter.

Horton started for Triple-A Iowa Sunday, so he is on the same schedule as Imanaga’s spot in the rotation. He has also been dominant of late — with only two runs allowed in his last 15.2 innings.

“Just trying to make sure it’s the right time,” Hoyer said of a potential Horton call-up. “I think it’s easier to work on things in the minors and he didn’t pitch a lot last year.

“Had he pitched all of last season, he may well have debuted by now. And if he debuted, you would have a better sense of where he is. Whereas because he missed a lot of time last year, I think it’s been good to give him some foundation in Iowa.”

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The Cubs have an off-day Thursday before the Mets series this weekend, so they have some time to sort through all the options. They also want to take a big-picture view on the entire season and don’t want to rush into a decision just to resolve the short-term.

“We have options on how want to pitch [Saturday in New York],” manager Craig Counsell said. “We’ve got some length in our bullpen, so we’ve got some ways to attack that game.”

One such length option in the bullpen is veteran Chris Flexen, whom the Cubs called up late last week. He signed a minor-league deal with the team in the offseason and pitched well in Triple-A (1.16 ERA) before getting the promotion to the majors.

He worked three shutout innings in Friday’s win over the Brewers and was stretched out as a starter in the minors.

Flexen has 110 career MLB starts under his belt, but he also could serve as a bulk option if the Cubs want to treat one of the games against the Mets as a bullpen day.

Brad Keller represents another length option in the bullpen, as he began his career as a starter with the Kansas City Royals. He has pitched exclusively out of the bullpen this season, however, and has not been stretched out — he has maxed out at two innings in two of his 13 appearances.

The Cubs also have young left-hander Jordan Wicks available in the minor leagues, but he has struggled this season – 6.38 ERA in five Triple-A games and a 13.50 ERA in two MLB relief appearances.

“No one’s going to be Shota,” Hoyer said. “But we have to have guys step up. Our depth is getting challenged a bit, but I think we still have pretty good depth and options.

“We’ll have to have those guys step up.”