The Astros activated Trammell (groin) from the 10-day injured list Tuesday.
Trammell was shelved for more than a month with a left groin strain but has been cleared to return after going 4-for-16 with a pair of home runs across four rehab games. With Zach Cole back in the minors and Joey Loperfido (quad/foot) having recently suffered a setback, the left-handed-swinging Trammell could see playing time versus right-handed pitching. He'll slot into the starting nine right away in Tuesday's game against the Rangers, occupying left field and batting fifth.