KANSAS CITY, Mo. -- Alex Smith’s career, one that has had its share of highs and lows, is at yet another tipping point.

Smith on Sunday was again unable to drag the Kansas City Chiefs from their free fall. His season, as well as that of the Chiefs, took another unexpected turn for the worse as they lost for the fifth time in six games, this time 16-10 to the Buffalo Bills at Arrowhead Stadium.

The Chiefs scored just one touchdown, and it was their only TD in the past nine quarters. Smith snuffed Kansas City’s hope for a late rally by throwing an interception in the final two minutes.

Smith and the 6-5 Chiefs were frequently booed by the home fans. Kansas City’s once commanding lead in the AFC West is down to a single game over the Chargers and Raiders.

Coach Andy Reid said he didn’t consider a change to Patrick Mahomes II at quarterback on Sunday and won’t make a switch for next Sunday’s game against the New York Jets.

Even if Smith keeps his starting job for the rest of the season, he’s making the decision easier for the Chiefs to switch to Mahomes next season. He’s also perhaps narrowing the market for his services among other teams.

One way or another, Smith faces an important stretch of games in December. If he can lead a revival, he’ll emerge as starter material, whether for the Chiefs or another team.

If not, he faces an uncertain future.

"Certainly frustrated, for sure," Smith said. "A little shock there, no doubt. Felt like we were going to bounce back, come back and get into rhythm on offense. Certainly from the get-go, we didn’t do that."

The rest of the offense is hardly faring any better than Smith. The running game has become a disaster. The Chiefs are dropping passes. Receivers are getting mixed up on too many plays, perhaps including the one on which Smith threw the interception. He blamed it on a "miscommunication" with Tyreek Hill.

The Chiefs afterward talked about providing more help to Smith. One such player was wide receiver Albert Wilson, who caught the touchdown pass, but also dropped a couple of passes in the first half.

"I’ve got to come in and give my quarterback a better look and get him in a rhythm early," Wilson said. "When he’s on fire, no defense can stop us.

"We’ve just got to get him going early and let him go out there and feel good and play ball."

Ultimately, it’s on Smith as the quarterback. Smith was the Chiefs’ MVP candidate when they were 5-0 and now he’s facing the heat as Kansas City is struggling on offense. The Chiefs punted after three plays on each of their first five possessions against the Bills.

"I guess mine goes with the offense," Smith said when asked how confident he was in his ability to get the Chiefs turned around. "When things are rolling, it’s great. You’re a product ... probably a reflection [of the larger offense].

"Didn’t get it done today and it’s frustrating. I think that confidence and momentum and rhythm, it’s all kind of the same thing I feel like I’ve been talking about the last two weeks. It can come and go, and certainly it took us a long time to get it going."

When they did, it wasn’t enough. The Chiefs are now in a fight to win their division.

Success in that task hinges on Smith winning his own personal battle.