Kansas City Royals right-hander Stephen Kolek will miss at least five to seven days and possibly longer after sustaining a left oblique strain.

Kolek felt tightness in his left side while warming up for a relief appearance during Wednesday's spring training game against the Seattle Mariners.

"(Kolek) is the guy that probably you would have put near the bottom of the list of guys who might get hurt," Royals manager Matt Quatraro told reporters on Thursday. "His arm's been healthy, and he's in great shape. He takes care of himself. And then something like this pops up. It's just unexpected."

Kolek, who turns 29 in April, is competing for a spot in the Kansas City rotation. He went 1-2 with a 1.91 ERA in five starts for the Royals last season after being acquired from the San Diego Padres along with fellow right-hander Ryan Bergert in exchange for catcher Freddy Fermin.

Kolek was 4-5 with a 4.18 ERA in 14 starts, including a complete-game shutout, for San Diego prior to the trade. Overall, he is 8-7 with a 4.01 ERA in 61 appearances (19 starts) with the Padres (2024-25) and Royals.