Falcons coach Bobby Petrino said Shockley will have an MRI exam on Sunday to asses the severity of the injury.
"It didn't look good," Petrino said. "I didn't like the way he looked on the field."
Shockley, a 2006 seventh-round draft pick, was hurt after attempting to cut to the inside of the field on a 10-yard scramble. Shockley's right foot slipped when he planted it at the Buffalo 15-yard line, causing his left leg to twist awkwardly before he was tackled by linebacker Josh Stamer.
Shockley was 4-of-5 for 46 yards passing and added 18 yards rushing on three carries. He was replaced by second-stringer Chris Redman.
"Obviously he's distraught," Atlanta quarterback Joey Harrington said. "That's not anything you like to have happen. It may be a little while before he's able to get going again."
Shockley didn't play in any Falcons games last season as a rookie.
Copyright 2007 by The Associated Press
