Kansas City Chiefs quarterback Alex Smith has a lacerated spleen and will miss Sunday’s game against the San Diego Chargers.

Chiefs trainer Rick Burkholder said Friday that Smith will heal on his own and would not need surgery. He said a normal recovery time from such an injury is six weeks.

The scan results showed a 3-centimeter laceration and a slightly swollen spleen.

Chase Daniel will start in Smith’s place. Daniel has one career start, which came last season in Week 17 and also was against the Chargers.

Smith took a hard hit to his abdomen in last Sunday’s 20-12 loss against the Pittsburgh Steelers. Smith said he noticed discomfort after the game but didn’t think he had a serious injury. He practiced fully on Tuesday and Wednesday this week.

–San Diego Chargers running back Ryan Mathews has been ruled out for Sunday’s key game against the Kansas City Chiefs with a sprained ankle. It will be the third straight game Mathews has missed.

Chargers wide receiver Keenan Allen has an outside chance to play Sunday, but he is listed as doubtful with injuries to his shoulder and ankle.

The Chargers need to win Sunday’s game to get into the playoffs.

–Arizona Cardinals quarterback Drew Stanton may be lost for the rest of the season after the team reportedly discovered an infection this week which required arthroscopic surgery.

The infection, discovered Wednesday, was believed to have been caused by an outside medical procedure, the NFL Network reported.

Cardinal coach Bruse Arians said earlier in the week that he hoped Stanton would be ready for the playoffs after missing the final two regular-season games with a sprained knee. The Cardinals (11-4) have already clinched an NFC playoff spot.

–Cleveland Browns head coach Mike Pettine announced that Connor Shaw will be the Browns starting quarterback Sunday against the Baltimore Ravens.

CBSSports.com reported Shaw signed a contract, officially allowing the Browns to elevate Shaw from the practice squad.

Shaw, an undrafted rookie out of the University of South Carolina, has been practicing with the first team all week, but this will be Shaw’s first NFL start.

Brian Hoyer has missed the entire week of practice with shoulder and biceps injuries, and Johnny Manziel is on injured reserve with a hamstring injury.

—The Carolina Panthers will start running back Jonathan Stewart for the fourth straight game with DeAngelo Williams listed as probable for Sunday’s NFC South showdown against the Atlanta Falcons.

Williams has missed the last three games for Carolina while dealing with a broken bone in his hand.

–Atlanta Falcons running back Steven Jackson likely will miss Sunday’s game against the Carolina Panthers with a quadriceps injury

Jackson and wide receiver Julio Jones (hip) were listed as questionable in Friday’s injury report, but there is a good chance Jones will play.

–Washington Redskins quarterback Robert Griffin III, dealing with soreness in his throwing shoulder, is listed as probable for Sunday’s game against the Dallas Cowboys.

–The San Francisco 49ers placed guard Alex Boone and defensive back Raymond Ventrone on injured reserve.

The 49ers also signed wide receiver Trindon Holliday to a two-year deal and promoted cornerback Cameron Fuller from the practice squad.

–The Tampa Bay Buccaneers agreed to a three-year contract extension with wide receiver Louis Murphy.

The 6-foot-2, 200-pound Murphy played in 11 games this season, with three starts, catching 31 passes for 380 yards and two touchdowns.

–Baltimore Ravens wide receiver Torrey Smith, whose contract expires after the season, said it’s a “horrible feeling” knowing the possibility he could be playing his final game with the team Sunday.

Smith will be an unrestricted free agent in March if the Ravens don’t use the franchise tag on him, which would cost approximately $12 million. He said this week that he would like to remain with the Ravens.

–The Chicago Bears signed center Roberto Garza to a one-year contract extension Friday.

Garza has played for the Bears since 2005 and missed just six games in that timeframe. He will be 36 years old in March.

–Seattle Seahawks running back Marshawn Lynch was fined $11,050 by the NFL for his actions while scoring a touchdown on Sunday.

To finish his 79-yard touchdown run in the fourth quarter of Sunday’s 35-6 victory over the Arizona Cardinals, Lynch did a backward dive into the end zone while grabbing his crotch.

–Oakland Raiders defensive end Justin Tuck was fined $22,050 for unsportsmanlike conduct after directing abusive language toward a referee in Sunday’s win over the Buffalo Bills.

–Detroit Lions pass rusher Ziggy Ansah was fined $22,050 for his hit to the head of sliding quarterback Jimmy Clausen in Sunday’s win over the Chicago Bears.