Martinez, who's made the club as one of the team's backup outfielders, was scratched from the lineup for Thursday's game against the Tigers, and he admitted going on the DL was a possibility. He missed a week earlier this spring with lower back tightness and will be examined by a doctor Friday in Houston.
"I think it's the [left] oblique right now," Martinez said. "I feel a little more pain right now than I did before. Hopefully a couple of days off and I'll be back."
Martinez said the team has discussed possibly having to put him on the disabled list. The Astros are taking a bevy of extra players to Houston, so they wouldn't have to go reach to find his roster replacement. Trevor Crowe and J.D. Martinez were among the last outfielders cut from camp.
Martinez is holding out hope he won't have to go on the DL.
"I can play like that, but sometimes when I throw and I swing I feel a little pain," he said.
The 24-year-old left-handed hitter batted .237 with six homers and 14 RBIs in 41 games last year for the Astros, who claimed him off waivers on Jan. 11, 2012.