LeMahieu (back) will start at second base and bat leadoff Sunday against the Mariners, Patrick Saunders of The Denver Post reports.
LeMahieu was held out of Saturday's 4-1 win with lower-back tightness, affording Pat Valaika a turn at the keystone. The injury was never considered significant, and the fact that LeMahieu was included in the starting nine for the Rockies' final game before the All-Star break rather than being rested implies as much.