Felipe Paulino could be headed back to the disabled list, which already includes three Kansas City Royals starting pitchers.
Paulino departed in the first inning with a right groin strain and the Royals went on to a 4-2 loss to the Minnesota Twins on Wednesday night.
The right-hander faced four batters and was injured when Justin Morneau flied out to center on his 13th pitch.
"He just felt something in his groin when he made the pitch to Morneau and broke to cover third base," Royals manager Ned Yost said.
Starting left-handers Danny Duffy, Jonathan Sanchez and Everett Teaford are already on Kansas City's disabled list. The Royals don't know yet if Paulino will be joining them. Paulino began the season on the DL with a forearm strain.
"We're going to be super disappointed if he's out, but the sun is going to come up tomorrow and major league baseball is going to be played and we've got to find a way to continue it," Yost said. "You can't dwell on it. You just make adjustments and move on."
Yost had planned on Paulino being a part of a four-man rotation through June 16 with off days Thursday and Monday.
"It does change your plan a little bit," Yost said. "There are always things that pop up over the year that you have to make an adjustment. Hopefully this won't be one of them, but we'll just have to wait and see what the extent of it and how bad it really is. Right now we just don't know.
"You just have to deal with it and continue to get through it somehow. You sure don't want to do it especially with a guy like Paulino the way he's been throwing. We're talking about options, looking at different things if this thing requires some time off what we're going to do."
Paulino is 3-1 with a 1.67 ERA in seven starts. He did not allow a run in four of his first six starts.
Nick Blackburn shook off a slow start and pitched five effective innings to pick up the victory. Justin Morneau hit a go-ahead, two-run single with two out in the fifth as Minnesota won for the fourth time in five games.
Morneau, Ben Revere and Ryan Doumit each had two hits.
Blackburn (2-4), who was making his first start since coming off the disabled list following a left quad strain, allowed two runs and five hits. He threw 92 pitches while lowering his ERA from 8.37 to 7.75.
"To be a part of a win when they didn't have to score seven for me is big, to be a part of a low-scoring win," Blackburn said. "I want to help this team out more."
Yuniesky Betancourt hit a two-run homer in the first, but that was it for the Royals. Four Twins relievers combined for four innings of two-hit ball, with Matt Capps tossing a perfect ninth to log his 14th save in 15 opportunities.
Luis Mendoza (2-3) replaced Paulino and pitched five innings, yielding two runs and five hits.
"Anytime your starter goes out that quick and you've got to go to the bullpen early, it's tough for a team," said Kansas City's Eric Hosmer, who extended his hitting streak to nine games. "But Mendy came in and did a phenomenal job. The offense could have done a little more. The pitching did a great job. This one's on the offense."
Morneau's bases-loaded hit in the fifth scored Revere and Jamey Carroll, giving the Twins a 3-2 lead. Revere also tripled and scored on Carroll's single in the seventh for Minnesota's final run.
The Twins scored an unearned run in the first after shortstop Betancourt committed an error. Doumit's double brought home Carroll, who reached on Betancourt's third error in five games.
NOTES: C Joe Mauer, who has a career .348 batting average against the Royals, did not play in the three-game series because of a sprained right thumb. Mauer hasn't swung a bat since the injury Sunday, but has been able to catch bullpen sessions. ... CF Denard Span, mired in an 0-for-14 skid, was held out of the Twins lineup. ... SS Alcides Escobar, who committed three errors in the previous four games and is hitless in his past 11 at-bats, was not in the Royals lineup, getting a breather. He had started 53 of the first 54 games. ... Twins LF Josh Willingham is hitting .361 in his 10-game hitting streak after a first-inning single. ... The Twins, who have the worst record in the AL, won their third straight series. ... Both clubs are off Thursday.