KANSAS CITY, Mo. — Alex Smith thought he had some indigestion. It turned out to be a lacerated spleen.

Now, the Kansas City Chiefs will put their already slim playoff hopes in the hands of career backup Chase Daniel, who will make his second NFL start Sunday against San Diego.

The Chiefs need to beat the Chargers and hope that Baltimore and Houston lose to reach the postseason for the second straight year. San Diego needs only to defeat its longtime AFC West rival to get back to the playoffs – and now faces a second-string quarterback.

“The guys have a lot of trust in Chase,” Chiefs Coach Andy Reid said shortly after Friday’s practice. “Our heart goes out to Alex. It’s not something he wanted to happen. He wanted to be out there. But the guys know Chase. They’re comfortable with him.”

Smith is expected to miss about six weeks, Chiefs trainer Rick Burkholder said, though his age and fitness level could shorten that timeframe. The Chiefs would need to make the playoffs and then likely advance all the way to the Super Bowl for him to return this season.

CARDINALS: Ryan Lindley was named the starting quarterback again, and Drew Stanton has been treated for an infection in his sprained right knee, a setback in his attempt to return for the playoffs.

Coach Bruce Arians initially said rookie Logan Thomas would start Sunday at San Francisco. But he said he changed his mind based on Thomas’ performances in practice.

Stanton, who has missed the last two games, experienced swelling in his knee on Wednesday. Arthroscopic surgery was performed Wednesday night to flush out the knee and treat it with antibiotics.

CHARGERS: Running back Ryan Mathews was ruled out of San Diego’s game Sunday at Kansas City, which the Chargers must win to clinch a wild-card berth.

Punter Mike Scifres was also ruled out.

SEAHAWKS: Running back Marshawn Lynch was fined $11,050 by the NFL for an inappropriate gesture made while scoring a touchdown against Arizona last Sunday.

Lynch appeared to grab at his groin as he leaped into the end zone to cap a 79-yard TD run while scoring in the fourth quarter of Seattle’s 35-6 victory.

BROWNS: Rookie quarterback Connor Shaw will come off Cleveland’s practice squad to start Sunday against Baltimore.

With Brian Hoyer still slowed by a sore right shoulder and rookie Johnny Manziel on injured reserve, Shaw, an undrafted free agent from South Carolina, will become the 22nd quarterback to start a game for the Browns since 1999.

WASHINGTON: Robert Griffin III is listed as probable for the season finale after taking part in a full practice.

Coach Jay Gruden said Griffin “looked good” and “made all the throws” Friday as Washington prepared for Sunday’s game against Dallas.

BILLS: Buffalo may be without two of its best defensive players against New England on Sunday.

Tackle Marcell Dareus and cornerback Stephon Gilmore are listed as doubtful, and neither has practiced this week after suffering injuries against the Oakland last Sunday.

SAINTS: The team placed running back Pierre Thomas and defensive lineman Akiem Hicks on injured reserve, ending their seasons.