It turns out Will Blackmon's knee injury won't heal in a timely manner, so the New York Giants placed the cornerback-return specialist on season-ending injured reserve Thursday and signed Brian Witherspoon as a replacement.
Witherspoon, a third-year pro, has played in 22 NFL games, mainly as a returner, with the Jacksonville Jaguars, Detroit Lions and Carolina Panthers, and he averaged 10.8 yards on 26 punt returns and 23.6 yards on 80 kick returns. He was waived by the Panthers before the start of the season.
Blackmon, who was signed as a free agent in late October, hurt his knee against the Philadelphia Eagles on Dec. 19 and missed Sunday's game in Green Bay. He averaged 6.7 yards on 14 returns in five games.
The Packers had released the fifth-year pro during training camp after reaching an injury settlement with him. He returned two punts for touchdowns in 2008.
The Associated Press contributed to this report.
