Crisp fractured the left finger again in the sixth inning of Saturday's 4-2 loss against the Twins, when he slid into third base while also being tagged out after coming around from first on a throwing error by pitcher Kevin Slowey.
He managed to stay in the game, and manager Bob Geren said on Sunday morning that Crisp will see a hand specialist in the Bay Area on Monday to determine if he can continue playing with the fracture.
"We'll know in the next day or two where he stands," Geren said. "Right now it's just sore, and he's day to day."
The 30-year-old Crisp was sidelined from April 3 to May 20 with the first fracture, which occurred when he was tagged by San Francisco's Juan Uribe while sliding into second base in an exhibition game with the Giants.
His indefinite absence will allow a handful of outfielders the opportunity to receive playing time. On Sunday, Geren placed Rajai Davis in center, with Chris Carter in left and Matt Carson receiving the start in right field.
Davis is likely to stay in center for the time being, and Geren has plenty other options on the corners, including Gabe Gross, Jeff Larish and Jack Cust.
Crisp was batting .316 with five homers, 20 RBIs, 26 runs scored and 18 stolen bases in his last 39 games, representing something of a sparkplug for a struggling A's offense.
"It's difficult to replace someone who's played as well as he has," Geren said. "There are good candidates to fill his spot, but I'm still hopeful he'll be able to play."