CHICAGO — In a way, Cade Horton came to the big leagues out of pure necessity.

To say that now sounds outlandish after the numbers he put up in 2025. Sure, he was the Cubs’ top pitching prospect and was always going to make his debut this season.

But in early May, injuries had already begun to haunt the Cubs’ starting rotation.

Justin Steele was ruled out for the season after just four starts. Shota Imanaga’s hamstring injury meant the team was temporarily down its top two starters from a season ago.

Enter the 23-year-old Horton, who stormed onto the scene on May 10 and never looked back. After some ups and downs, he settled in and became one of MLB’s most dominant pitchers in the second half (1.03 ERA, 61.1 IP) as well as a leading National League Rookie of the Year candidate.

The Cubs simply needed another starter four months ago. Horton became that and so much more: An 11-4 record, a 2.67 ERA and 118 innings were the fruits of his labor. With the way he was rolling, he likely would have been a Game 1 starter in the playoffs.

But that’s no longer on the cards for Horton, who landed on the 15-day injured list on Saturday with a fractured right rib. He’ll miss a chance at pitching in the NL Wild Card Series, which the Cubs will host beginning on Tuesday.

“It’s a blow. There’s no question about it,” manager Craig Counsell said after the Cubs’ 7-3 win over the St. Louis Cardinals. “Losing players to injury at this time of year — it’s not fun. Everybody knows that. And it hurts.”

In the Cubs’ clubhouse after the game, Pete Crow-Armstrong stared off into the distance when asked about longtime teammate Horton.

“I mean, not what you want to hear,” Crow-Armstrong said, pausing for a beat. “But I think he’s going to be fine. He’s a guy who’s got his focus in the right place. We already know that he’s going to do everything he can to just get healthy.

“Selfishly, yeah, I want him taking the ball every chance he can get. But at the same time, selfishly, I want to be playing with him for a long time, so I hope we do whatever we need to do to keep Cade Horton healthy overall.”

Part of that plan will mean sharing the wealth and turning to the veterans in the Cubs’ pitching staff, said Counsell.

“It means that other guys are going to get an opportunity,” Counsell said. “To have a chance to impact the game, have success and control what happens.”

In anticipation of Horton’s injury news, Jameson Taillon was thrust into starting a crucial game at Wrigley on Saturday. Taillon said postgame he was originally supposed to take the ball in Sunday’s finale, but he was moved up because he may now have to plug the gap that Horton’s absence will leave in the playoff rotation.

And much like Horton did when he arrived in MLB, Taillon stepped in Saturday to spin a six-inning, one-run gem that was perhaps a preview of what he’ll set out to do when it matters most next week.

“I showed up today and just really wanted to help the guys get it done,” Taillon said after earning his 11th win of the season. “So, today felt pretty important.”

Taillon, who has spent time on the IL in two separate stints this year, knows entirely too well what it’s like to miss out.

“Cade’s been incredible. He’s fit right into our team. I know it hurt him a lot to have to go on the IL and not be a part of the first round,” Taillon said. “That says a lot about him. He just wants to be a part of the team and wants to help.

“He picked us up a lot this year when I was down for a while, Shota was down for a while. So now it’s our turn to try to pick him up and make sure he can hopefully play a part as we get going into the playoffs.”