Treinen (back) will not pitch in any postseason games, Shayna Rubin of The San Jose Mercury News reports.

EDGE Analysis

The issue is serious enough that the A's can already rule Treinen out for games that could take place weeks from now. However given his struggles prior to the injury (4.91 ERA, 1.62 WHIP in 58.2 innings), this seems like a common sense move even if he were medically cleared.