The coach said the procedure went "really well" and indicated he is hopeful the signal-caller will play again this season, The Kansas City Star reported.
"We're just giving as much time as we can to see where he is, and as we make decisions, we're going to let you know," Haley said. "But we have not done anything with Matt yet, as far as his status."
Cassel hasn't been placed on the injured reserve list. He hurt the hand late in the Chiefs' 17-10 loss to Denver Sunday.
"I would say there is potential [for a return]," Haley told reporters, "but that really depends here on this first week and how things go."
The Chiefs will go with backup Tyler Palko in the meantime, with rookie Ricky Stanzi waiting in reserve.
Notable deaths of 2014 [PHOTOS]
Michael Sam cut from the Dallas Cowboys