Marinez suffered a hamstring injury while warming up in the fifth inning of Thursday's game against the Rangers, Rich Dubroff of BaltimoreBaseball.com reports.
He gave up two runs on two hits and three walks in the fourth inning and came back out to eat some innings in the fifth inning but was unable to get through his warm-up pitches. For now he should be considered day-to-day, although he could end up on the disabled list.