"In the ballgame, he left the game with cramps," coach Mike Smith said. "But 24 hours after the game, he was starting to feel the ankle. When the adrenaline wore off he had an ankle issue.
The Falcons don't believe the injury is serious.
"We're hoping that we'll get him back out [Thursday] and get him some reps."
Weatherspoon, the team's first-round draft pick, and middle linebacker Curtis Lofton lead the team with 27 tackles each. If Weatherspoon isn't able to return quickly, Stephen Nicholas, last year's starter, could return to the lineup.
Needless to say this would be a huge loss if Spoon can't go. The Falcons should be able to beat the 49ers without him but in these rivalry games anything can happen. Hopefully, he's back out there on Thursday preparing to introduce himself to Frank Gore.