The Royals activated Kolek (oblique) from the 15-day injured list Tuesday.
Kolek is set to make his season debut for the Royals with a start Tuesday versus the Guardians, slotting in as a replacement for Noah Cameron (back). Out since spring training with an oblique strain, Kolek posted a 2.76 ERA and 14:4 K:BB over 16.1 innings in four rehab starts with Triple-A Omaha. He threw 72 pitches in his final rehab appearance, so he could be limited slightly from a workload perspective Tuesday.