Karns finished the Cactus League season with a 1.98 ERA and 18 strikeouts in 13 2/3 innings.
"My stuff is playing," Karns said. "I think we're filling the zone. I think we're being able to stay ahead. From first pitch of each at-bat, we were able to get ahead. I think with that it's going to allow me to create that type of swing and miss stuff."
Grimm debuts Right-hander Justin Grimm, who signed on Sunday, made his first appearance in a Cactus League game for the Royals in the eighth inning. Grimm gave up two hits and a walk, but he escaped without allowing a run by striking out Weston Wilson and retiring Corey Ray on a flyout to right to end the frame.
"He was a little rusty, you could tell," manager Ned Yost said. "But he got his way through it."
Yost said Dozier will play first quite a bit there, as well as outfield and third base. Yost also said O'Hearn will play some outfield, too.
Camp battles Right-hander Burch Smith, a Rule 5 Draft pick who is perhaps on the border of making the 25-man roster, helped his cause with two scoreless innings. He gave up one hit and struck out two. "He looked good," Yost said.
Outfielder Michael Saunders, who likely only makes the 25-man roster if the Royals opt to carry five outfielders, went 1-for-3 with an opposite-field single.
Injury update Outfielder Paulo Orlando, recovering from a hamstring strain, was back in the lineup on Wednesday night and said he felt fine on Thursday morning.
Infielder Adalberto Mondesi, battling right shoulder impingement, continues to throw long toss (90 feet). He was the DH on Thursday and had two hits.
Outfielder Bubba Starling is still out with a strained oblique. He is likely a 60-day disabled list candidate.
Up next Watch live on MLB.TV as right-hander Jakob Junis, likely the No. 5 starter in the rotation, starts at 3:05 p.m. CT on Friday in a split-squad game against the Giants at Scottsdale Stadium. Left-hander Brian Flynn, and right-handers Seth Maness and Mike Broadway also are expected to throw.
In the other split-squad game on Friday at Surprise Stadium, right-hander Ricky Nolasco, a non-roster invite, will start against the Dodgers at 3:05 p.m. CT. Left-handers Eric Skoglund and Tim Hill, and right-hander Wily Peralta also are expected to throw for K.C.