The Royals will further evaluate Paulino's injury during Thursday's open date. His next scheduled start would be Tuesday night against Milwaukee.
The injury occurred after Paulino was drilled on the same leg by a Ben Revere line drive in the first inning, but the club announced that the two events were not related. Paulino hurt his groin while making his last pitch to Justin Morneau, the last batter he faced. He was replaced by Luis Mendoza.
Revere, the Twins' leadoff batter, hit a line drive that struck Paulino in his right thigh as he followed through on his 2-1 pitch. As the ball bounced off him toward the first-base line, Paulino scrambled after it, recovered and attempted a flip to first baseman Eric Hosmer.
The ball glanced off Revere and bounced away behind first base. Revere raced all the way to third base but was called out for interfering with Paulino's throw by being inside the three-foot lane approaching first base.
Head athletic trainer Nick Kenney and manager Ned Yost checked out Paulino, who took some test throws and remained in the game.
"It bruised my leg, but it wasn't anything close to my groin," he said.
The next two batters reached base before Morneau hit a high fly to center field. With Josh Willingham on third base, Paulino started to back up a possible play at the plate.
"I just felt it on the pitch with Morneau and, after that pitch, I tried to go back up home plate on the fly ball. But I stayed there and said, 'Oh, no!' " Paulino said.
He remembered 2009 when he tried to pitch through a right groin strain and it got worse. As a result, he was out for 20 days.
"It was just not my day today, unbelievable," Paulino said. "But the good thing right now is it's no big deal. My groin is just a little bit strained and hopefully tomorrow there will be less inflammation in that spot."
The injury kept the Royals from making a roster move for their Interleague series at Pittsburgh this weekend. They planned to add another bench player, probably first baseman Clint Robinson, while returning left-handed pitcher Ryan Verdugo to Triple-A Omaha. But the uncertainty over Paulino's status has delayed that.
Robinson has a .314 average, eight home runs and 37 RBIs for the Storm Chasers. He would be making his big league debut at age 27.