MESA, Ariz. — Jameson Taillon was a last-minute scratch prior to his spring debut.

The righty threw “about 10 pitches” in his mound warmup, per manager Craig Counsell, when he felt tightness in his lower back. Counsell said the Cubs hope to have a clearer idea on his status on Sunday. They have no plans for any imaging at this moment. 

“Let’s see what see what happens overnight and have kind of more guidance on what we’re gonna do here,” Counsell said after the Cubs’ 5-0 win over the Rockies at Sloan Park.

Lefty Thomas Pannone, a non-roster invitee, started in his place.

Taillon had dealt with some calf soreness earlier in camp, but he was still on the same schedule as the rest of the Cubs starters.

He is expected to be a key piece of the Cubs rotation in 2024. He finished with a flurry, posting a 3.38 ERA over his final 16 starts after really struggling in the first half of the season. Taillon had a 6.93 ERA and opponents had an .870 OPS off him. The Cubs had lost 12 of his first 14 starts.

The righty signed a 4-year, $68-million contract prior to last season and the success in the second half of the season had led to expectations that he would be a key piece atop the Cubs rotation this season.

If he misses any sort of time to start the season, the Cubs can turn to some in-house options to fill in the rotation. The Cubs leading rotation candidates outside of Taillon are Opening Day starter Justin Steele, Kyle Hendricks, Shota Imanaga and Jordan Wicks.

Drew Smyly, Javier Assad and Hayden Wesneski are all being stretched out this spring and can and will likely make starts for the Cubs at some point in 2024. They also have depth in the upper levels of the minor leagues in players like Ben Brown and top prospect Cade Horton.