Here are the most significant NFL injuries in Week 13:
Ryan Shazier, LB, Pittsburgh Steelers: Shazier was carted off the field with a back injury after a collision with Bengals receiver Josh Malone early in the first quarter. The scene was somber as teammates looked emotional kneeling around Shazier, who was down on the grass for a few minutes at the 10:58 mark. Shazier led with his helmet into Malone's thigh, then signaled to trainers as he rolled on the ground and appeared to hold his lower back. He was taken from the field on a backboard, and left the stadium by ambulance to be taken to a local hospital.
Second-year linebacker Tyler Matakevich filled in for Shazier.
Vontaze Burfict, LB, Cincinnati Bengals: Burfict was declared out of Monday's game with a head injury after being taken off the field on a backboard. Burfict was in and out of the game with various injuries, but collapsed to the ground after taking a blindside hit from Steelers wide receiver JuJu Smith-Schuster. Burfict was loaded onto a backboard and carted off, but later jumped off the cart and walked into the Bengals locker room on his own, according to ESPN's Lisa Salters.
Joe Mixon, RB, Cincinnati Bengals: Mixon appeared to take a shot to the helmet while being tackled by a group of Steelers, and remained on the ground while being examined by Bengals medical personnel. He was helped off to the sideline, and entered the medical tent to be examined. He subsequently went back to the locker room to be evaluated for head and shoulder injuries. He was subsequently declared out for the remainder of the game, due to a concussion.
Adam Jones, CB, Cincinnati Bengals: In the course of intercepting a Ben Roethlisberger pass in the first quarter, Jones injured his groin. Originally declared questionable to return, he was subsequently downgraded to out.
Zach Ertz, TE, Philadelphia Eagles: In the process of attempting to haul in a pass in the third quarter, Ertz appeared to bang his helmet on the turf. He was brought back to the locker room to be evaluated for a head injury, and the Eagles initially declared him questionable to return before downgrading him to out.
Alec Ogletree, LB, Los Angeles Rams: After being responsible for a pick-six in the first half, Ogletree was announced as having injured his elbow. The Rams declared him questionable to return. During the second half, he was spotted with his arm in a sling, and downgraded to out. Bryce Hager replaced Ogletree in the lineup.
After the game, Ogletree said he hyperextended his elbow, but was hopeful of being able to play in the team's next game.
Matthew Stafford, QB, Detroit Lions: After throwing a fourth-quarter interception, Stafford went to the locker room, accompanied by Lions medical staff and with his throwing hand wrapped in a towel. He was declared questionable to return. Jake Rudock replaced him on the next possession. Stafford's hand was bandaged when he appeared at his postgame news conference, but the injury is being called a bruise, as X-rays were negative.
Tyrod Taylor, QB, Buffalo Bills: After battling through a knee injury during Sunday's game, Taylor was carted off to the locker room during the fourth quarter. The Bills quickly declared that Taylor would remain out for the duration of the contest. He was replaced by Nathan Peterman.
Taylor came off the field after a third-down incompletion in the fourth quarter and was carted off during the Patriots' ensuing offensive series.
After the game, Bills coach Sean McDermott indicated that Taylor had suffered the injury in the first quarter but was unsure on Taylor's availability for next week.
Jimmy Smith, CB, Baltimore Ravens: After dealing with Achilles tendon issues earlier this season, Smith fell to the ground late in the second quarter while trying to cover a deep route and writhed in pain with his face in the grass. His left Achilles tendon was examined by Ravens medical staff, and he was assisted off the field. The Ravens quickly declared that Smith would be out for the duration of the game, and he was replaced in the lineup by Marlon Humphrey.
After the game, ESPN's Adam Schefter reported that Smith will miss the rest of the season because of a torn Achilles tendon.
Tre'Davious White, CB, Buffalo Bills: A woozy-looking White was walked to the locker room to be evaluated for a head injury in the fourth quarter of Sunday's game. Trainers held each of his arms after White was elbowed in the back of his helmet by Patriots TE Rob Gronkowski after an interception as White lay face down on the field.
After the game, Bills coach Sean McDermott confirmed that White is in the concussion protocol.
Logan Ryan, CB, Tennessee Titans: Ryan appeared to take a knee to the head while making a tackle. He was examined in the medical tent before heading back to the locker room. After the game, the Titans confirmed that Ryan is in the concussion protocol.
Kyle Long, OG, Chicago Bears: A shoulder injury sidelined Long during the third quarter against the 49ers, and he was declared questionable to return. Tom Compton took over for Long at right guard for the Bears.
Leonard Johnson, CB, Buffalo Bills: Johnson was declared questionable to return because of a knee injury. He jogged to the locker room in the third quarter after being evaluated on the sideline. He was replaced by Lafayette Pitts, who had played 12 defensive snaps in the NFL before this game.
Shaq Lawson, DE, Buffalo Bills: Lawson was injured while defending a goal-line run in the third quarter and had to be assisted off the field. He was subsequently carted to the locker room and declared questionable to return with an ankle injury.
C.J. Fiedorowicz, TE, Houston Texans: After having sustained two concussions earlier this season, Fiedorowicz was back in the concussion protocol during Sunday's game against the Titans. He was downgraded to out in the second half.
C.J. Mosley, LB, Baltimore Ravens: Mosley went into the medical tent with a stinger during the second quarter, the second time he's been in the concussion protocol in six days. Kamalei Correa replaced him at inside linebacker. After being tested, Mosley was cleared to return to the game.
Wagner was later downgraded to out.
Cordrea Tankersley, CB, Miami Dolphins: Tankersley was injured during the first quarter against the Broncos and left the field under his own power after being attended to on the field. The Dolphins declared him questionable to return because of a shoulder injury. He made his return to the game later in the first quarter.
During the second quarter, Tankersley injured his ankle, and the team declared him questionable to return.
Pernell McPhee, LB, Chicago Bears: McPhee was evaluated on the sideline for a shoulder injury during the first quarter, and the team declared him questionable to return. If McPhee cannot return, it leaves the Bears with only two outsider linebackers in the active lineup.
While the Falcons did not change Levitre's official status, he was spotted on the sidelines without a helmet during the second quarter.
David Morgan, TE, Minnesota Vikings: Early in the first quarter, the Vikings announced that Morgan was in the concussion protocol. Later in the first quarter, the Vikings announced that Morgan was out for the duration of the game.
Dak Prescott, QB, Dallas Cowboys: Prescott injured his right hand in the second quarter of the Cowboys' win over the Redskins when his hand was hit by linebacker Josh Harvey-Clemons just as the QB made an option pitch to Rod Smith. He underwent X-rays on the hand and ended up not missing any time in the game because of a punt return TD by Ryan Switzer. Prescott was diagnosed with a bruise on his hand and is not expected to miss any time, according to ESPN's Todd Archer.
Trent Williams, OT, Washington Redskins: Williams left briefly in the third quarter before making his return. He is slated to undergo knee surgery at some point, but the determination hasn't been made yet as to when that will be, as it will end his season.
"There's some merits to sticking and trying to finish the season," Williams said after the game, per ESPN's John Keim. "I fought through it this long. Hopefully I can get another four games out of it."