Walker's rehab assignment shut down

Walker's rehab assignment shut down

MILWAUKEE -- Nationals reliever Tyler Walker has been shut down because of an ailing shoulder. Walker, who is on the 15-day disabled list because of the injury, made four rehab appearances and was hit hard, allowing six runs in 4 1/3 innings.

"Walker is not feeling that good," manager Jim Riggleman said. "He has not responded as well as we would have liked. He threw a game, and he was OK. He threw another game, and the shoulder wasn't OK."

There is no timetable on when Walker will pitch again.