Royals’ Stephen Kolek Diagnosed With Oblique Strain

Royals righty Stephen Kolek has been diagnosed with a “Grade 1+” strain of his oblique, per Anne Rogers of MLB.com. Kolek’s original diagnosis of a strain came yesterday, but the Royals sent him for additional testing — the results of which they’ve now received. He’ll be shut down entirely for about a week before being reevaluated.

Even milder oblique strains can cost players upwards of a month. That the Royals are deeming this a Grade 1 “plus” suggests it’s on the more severe side for a Grade 1 strain. A firm timetable won’t be known until he’s reevaluated after his shutdown, but with Opening Day one month out and Kolek in no-throw mode for the next week, it seems fair to suggest this calls his availability for the season opener into question.

Kolek had an uphill battle to claiming a spot in a rotation currently occupied by Cole Ragans, Seth Lugo, Michael Wacha, Noah Cameron and Kris Bubic, but he’s at or near the top of the list for sixth starter options in Kansas City. The 28-year-old righty, who came to the Royals alongside Ryan Bergert in the July trade sending catcher Freddy Fermin to San Diego, started 19 games between the Friars and Royals in 2025 and posted a combined 3.51 ERA. His 16.7% strikeout rate was well south of the 22.2% league average, but his 6.7% walk rate was strong (compared to the 8.4% average) and Kolek kept more than 51% of batted balls against him on the ground.

Since Kolek has minor league options remaining, he might be bound for Triple-A even if he’s able to return to the mound and sufficiently ramp up in time for Opening Day. A lengthier absence would compromise Kansas City’s depth, although they’ve improved on that front over the past year.

Cameron’s breakout showing as a rookie gave the Royals another viable big league rotation arm alongside their slate of veterans. He faded after a historically excellent start but still finished the season with a 2.99 ERA, 20.5% strikeout rate, 7.7% walk rate and 41.4% ground-ball rate. Bringing in Kolek, Bergert and swingman Bailey Falter at last summer’s deadline and righty Mitch Spence in a swap with the A’s earlier this month gives Kansas City several more arms to join the mix — all of whom (except Falter) have minor league options remaining.