"It's touchy, there's no doubt about it," Mills said. "There's no way we want to put anybody in harm's way. Are we getting close to that with the guys in the 'pen? Yes. Is that a concern to me? That's a drastic concern to me. It really bothers me, but at the same time we don't have an off-day for another week."
The Astros used six relief pitchers Tuesday, four of whom threw more than one inning. Closer Brandon Lyon wasn't available, because of a heavy workload, and Mills said starter J.A. Happ was next in line to pitch had the game dragged on.
On Wednesday, Mills made three pitching changes in the seventh inning so he wouldn't put too much of a burden on any one pitcher. Wilton Lopez and Tim Byrdak each faced one batter and threw three pitches, and Mark Melancon threw only five.
"We probably need to give some guys a rest today," Mills said. "[Jeff] Fulchino should be fine, and [Fernando] Abad and [Gustavo] Chacin for sure should be fine. Melancon is OK. It's going to be tough to mix and match like we'd like to."