Here are the main injuries we're monitoring after Week 13's Sunday action.
Zach Mettenberger, QB, Tennessee Titans (shoulder): Mettenberger suffered a Grade 1 sprain of the AC joint in his throwing shoulder in Tennessee's loss to the Houston Texans. The sixth-round pick reportedly told teammates that he would be ready to go against the Giants next Sunday, but we'll see what the MRI says. Jake Locker, who threw an interception in his first pass as Mettenberger's replacement, would be the starter if Mettenberger can't go. At this point, the 2-10 Titans are just trying to find out who can help them most next season.
Justin Hunter, WR, Tennessee Titans (spleen): A more serious injury happened to Hunter on an early Mettenberger interception against Houston, when Texans safety Danieal Manning lit Hunter up. Hunter returned to the game after a brief rest, but ultimately had to leave the game, and for good reason -- Hunter had stomach pain that worsened, and he was eventually taken to the hospital, where he was diagnosed with a ruptured spleen. At this point, it would be surprising if Hunter played again this season.
Brett Keisel, DE, Pittsburgh Steelers (triceps): Big and bad news for the Steelers as they try to keep pace in the ultra-competitive AFC North -- Keisel tore his triceps in Pittsburgh's Sunday loss to the Saints, and if that diagnosis holds up, he'll be out for the rest of the season. The 13-year veteran came back to Pittsburgh on a two-year, $3 million contract, and was primarily successful on passing downs this season. A serious injury may have him hanging it up for good.
Tyrann Mathieu, DB, Arizona Cardinals (thumb): The Cardinals have lost two straight games, and their former status as the absolute leaders in the NFC playoff race has dissolved completely. The reason for this is the team's injury situation -- head coach Bruce Arians and defensive coordinator Todd Bowles have done a lot of great things despite those injuries, but things are starting to catch up with them. Mathieu, who came back from a torn ACL suffered last season and was playing well, fractured his thumb on Sunday against the Falcons, but believes he'll be ready to play out the string. Todd Bowles' defense would not be the same without him. Tony Jefferson, who plays well against the run, would be Mathieu's primary replacement if that changes.
Torrey Smith, WR, Baltimore Ravens (leg): Smith was not on the field for Baltimore's last and crucial drive in the Ravens' loss to the Chargers, despite catching two touchdown passes from Joe Flacco in amazing fashion. After the game, Smith was seen limping around the locker room, though neither Smith nor head coach John Harbaugh would comment directly on the possible injury.
“That’s something that coach and I will have to address," Smith said of his absence late in the contest. "I don’t know when I am supposed to be going and when I am not supposed to be going. I’ll let coach handle it.”
Andre Ellington, RB, Arizona Cardinals (hip): Ellington, who has played most of the season with a foot injury, suffered a hip pointer in the fourth quarter of Arizona's loss to the Falcons. Ellington said after the game that this pointer is different than the other hip injury that has been bothering him of late. Arizona faces the Chiefs next week, and if Ellington can't go (reports suggest he could return either this week or next), the Cardinals' running game could look quite anemic.
Vontae Davis, CB, Indianapolis Colts (concussion): Davis suffered a concussion against the Redskins, which didn't really matter because Andre Luck was on fire, and Colt McCoy was struggling. But Davis might be the best cornerback in football this season, and it will obviously be important to have him for the stretch run -- Indy's pass defense generally falls way down when Davis isn't in there. He'll go through the standard NFL concussion protocol this week in preparation for the Colts' game against Josh Gordon and the Browns next week.
Rashad Jennings, RB, New York Giants (ankle): Jennings sat out the last two drives in the Giants' loss to the Jaguars with an ankle injury, which doesn't bode well for his return against a Titans defense next Sunday that can't seem to stop anyone. Andre Williams, who is more a bruiser who complements Jennings' slashing running style, would go in Jennings' place.
DeSean Jackson, WR, Washington Redskins (knee): As if the Redskins' passing offense wasn't weird enough this season, there's now the fact that Jackson, the team's primary deep threat, suffered a fibula contusion against the Colts. He said after the game that he didn't know whether he would undergo an MRI on Monday.