Walker (nose) has been ruled out for the remainder of the season, Bob Nightengale of USA Today reports.
It was originally thought the Walker was dealing with a deep bruise after being struck by a pitch during his eighth-inning at-bat in Monday's loss, but further tests revealed a sinus fracture. The 27-year-old hit just .163/.226/.388 with three homers in 37 games with the Diamondbacks this year.