Hunter walked off the mound with the help of a trainer in the third inning because of a strained right groin Thursday as Texas beat the Cincinnati Reds 15-13.
"I don't know the severity yet," Rangers manager Ron Washington said. "He was just told this morning he made the rotation then he pulled a groin. You never know what can happen in this game. That's why you have pitching depth. A couple of guys got sent out that were a little disappointed. Now they may be back in the mix."
"I think I'll be all right," Hunter said.
"Three days ... I had three days to go. It's all right. We'll get back together and go throw," he said.
Hunter has a 10.97 ERA in his three spring starts. He allowed a three-run homer to Jonny Gomes prior to his early exit.
Reds star Scott Rolen was hit by a pitch from Hunter in the first inning. The sure-handed third baseman made two errors in the third and was removed for a pinch-hitter because he was unable to hold the bat.
"Rolen had stitch marks on his elbow," Cincinnati manager Dusty Baker said. "I didn't hear anything, so no news is good news."
Nelson Cruz drove in six runs with a grand slam, an RBI single and double off Travis Wood. Cruz was struggling with a .184 average in 49 at-bats before his first home run this spring.
"It's nice to see him swinging the bat, especially where he was hitting the ball," Washington said. "All spring he's been pulling off the ball. It was nice to see him use right-center field because he's a big man. You don't have to use one part of the field, just hit the ball where it's pitched."
Wood gave up the grand slam in the inning in which Rolen had problems in the field.
"I felt good," Wood said. "I just got in trouble that third inning there. I ended up giving up a grand slam. That hurts but we were able to battle back as a team."
Wood helped bring his team back with an RBI double. He hit a two-run homer in his last outing on Saturday. He left the game with a lead in his longest outing this spring.
"Wood threw the ball good," Baker said. "We threw the ball around that one inning. You need some help from your friends. That one inning, he didn't get much. His pitch count was where we wanted to get it."
Dave Sappelt hit a two-run homer for the Reds and raised his average to .553 with three home runs. He started as a long shot to make the team but has turned some heads.
Chris Davis hit his fifth home run off Jose Arredondo. Davis leads the Rangers with 17 RBIs.
NOTES: Bronson Arroyo was scheduled to pitch in a minor league game for the Reds on Thursday. He was scratched Monday with the flu. He threw 85 pitches on Thursday. ... Reds LHP Dontrelle Willis, trying to revive his career, threw a scoreless inning in a minor league game after a bad outing on Wednesday.