Shoulder issues forced Crain to miss the entire 2014 season. He posted a 0.74 ERA in 36 2/3 innings in '13.
Other injury news
• First baseman Adam LaRoche was scratched from Wednesday's game because of tightness in his back, but manager Robin Ventura expects him to play Friday.
"He could play today, but with the off-day coming tomorrow, it's better to get him out of here, and he gets two days [off]," Ventura said.
LaRoche also dealt with some back tightness down the stretch last season with the Nationals.
• Center fielder Adam Eaton missed his second consecutive game with a stomach bug. He's expected to return to the lineup Friday.
AJ Cassavell is a reporter for MLB.com. Follow him on Twitter @ajcassavell. This story was not subject to the approval of Major League Baseball or its clubs.