Stanek's exit from Sunday's game against the Angels after facing just one batter was due to back spasms, MLB.com reports.
Stanek issued a four-pitch walk to Mickey Moniak and was then visited by manager Scott Servais and a trainer before being pulled from the game. Servais subsequently clarified that back spasms were the source of the abrupt exit but did not provide any semblance of a return timetable for Stanek. The right-hander will naturally have an opportunity to recover during the All-Star break, but whether that will be enough time for Stanek to regain full health remains to be seen.