Yarbrough (groin) threw a successful bullpen session Thursday, Marc Topkin of the Tampa Bay Times reports.
It is unclear when Yarbrough will return to game action, but this was a positive step. Topkin reported Thursday that the Rays will have three starting pitchers and two spots for openers at the outset of the season. Yarbrough would figure to be one of the primary pitchers on the days when an opener starts if he can get up to speed by the start of the season.