A hand specialist confirmed that Baez has a hairline fracture on his left thumb, and he's unlikely to play again in September, Gordon Wittenmyer of the Chicago Sun-Times reports.
Baez isn't expected to return to action before the regular season comes to an end, so he'll begin rehabbing with the hope of being activated for the playoffs, should the Cubs qualify. With Addison Russell still in concussion protocol, look for Nico Hoerner to see the majority of the playing time at shortstop down the stretch.