The Pirates purchased the contract of fellow right-hander Tim Wood from Triple-A Indianapolis on Friday.
Meek was out almost four weeks earlier this season for the same reason. An All-Star last year, he is 1-1 with a 4.40 ERA. He gave up nine hits in 3 1/3 innings over his past three appearances.
Meek will be examined by Dr. James Andrews on Monday.
Wood had 13 saves and a 2.96 ERA in 23 games for Indianapolis. He pitched 44 games for the Florida Marlins the past two seasons.
Pittsburgh put catcher Chris Snyder on the 60-day disabled list. He had back surgery this week is expected to return late in the season.