Herndon was injured making the tackle on Tampa Bay's Joey Galloway during a leaping 44-yard reception late in the first quarter. Seattle already was playing without Marcus Trufant, who has a sprained ankle.
PLAYOFFS: The New York Giants completed a rollercoaster ride to the playoffs Sunday, earning the final NFC wild card berth when St. Louis, Houston and Carolina posted victories.
The Giants (8-8) will play at Philadelphia, which won the NFC East title when Dallas lost to Detroit.
New York virtually assured itself of back-to-back postseason appearances for the first time since 1989-90 when it defeated the Washington Redskins 34-28 on Saturday night. The win was only the Giants' second in their final eight games.
The playoff appearance was guaranteed when Houston defeated Cleveland 14-6 and Carolina knocked off New Orleans 31-21. The results assured New York it would beat Green Bay had they finished tied.
COLTS: Peyton Manning moved into seventh in career touchdown passes when he connected with an unfamiliar target - defensive tackle Dan Klecko - early in the second quarter.
Manning's 2-yard scoring throw, his 30th of the season, capped a drive that lasted 10:09 and gave the Colts a 7-3 lead. It was his 274th career touchdown pass, breaking a tie with Joe Montana (273). Former Colts quarterback John Unitas is sixth in NFL history with 290.
INACTIVE: Chicago starting cornerback Charles Tillman and Green Bay wide receiver Greg Jennings were inactive for Sunday night's game.
Tillman missed his second consecutive game because of a sore back, while Jennings was nursing an ankle injury.
Ruvell Martin started for Jennings, who had 45 receptions and 632 yards as a rookie. Chicago's Ricky Manning Jr. started for Tillman.
RECORD-BREAKER: Detroit's Mike Furrey had 11 catches in the season finale Sunday to finish with 98, the most ever by a non-rookie after a season when he had no catches.
Furrey's 10-yard reception in the third quarter of the Lions' 39-31 victory over the Dallas Cowboys was his sixth of the game, giving him the record that he extended. Furrey is a fourth-year player who started 11 games as a defensive back for St. Louis last season.
Lionel Taylor had 92 catches for Denver in the AFL in 1960, the previous mark for the most catches by a non-rookie after a season with zero. Arizona's Anquan Boldin had 101 catches as a rookie in 2003, the most catches by any player with none the previous season.