Rainey is dealing with forearm tightness Saturday and won't pitch for several days, Byron Kerr of MASNSports.com reports.
Rainey underwent an MRI on his forearm that came back negative, but manager Dave Martinez said Saturday that he'll get a few days off to recover. The right-hander carries a 2.66 ERA and 0.74 WHIP over 20.1 innings this season.