Crawford has missed nine straight games with the injury and there's no timetable for his return.
"Jamal told me he's feeling better," Clippers Coach Doc Rivers said Sunday. "It's just that it doesn't seem like it. Honestly, we don't know. There's no target date for Jamal, for sure."
Crawford sustained the injury in the second quarter of a game against the Minnesota Timberwolves on March 9. A Clippers spokesman said the team's trainer, Jasen Powell, compared the injury to a UFC athlete getting kicked in the calf.
Crawford entered the locker room before Sunday's game noticeably having trouble walking.
He's had to rest and has only been able to do pool work, while receiving massages and circulation treatment.
Crawford, the reigning sixth man of the year, is the third-leading scorer on the Clippers, averaging 16.4 points and 2.5 rebounds a game. The Clippers have only 12 games remaining in the regular season and are in fifth place in the Western Conference, with a record of 45-25.
Rivers was asked after Friday's win over the Washington Wizards whether there's a chance Crawford might not return at all.
"There is a chance," Rivers said Friday. "I don't know right now because he's improved, but not enough, I'll tell you that. He's nowhere near, in my opinion, playing. We just have to hope he gets better."