This is the San Francisco 49ers' five-week season: Even the kicker suffered an injury that likely cost them a game.

The 49ers had a 10-point lead in the fourth quarter on Sunday and everything seemed fine, but then there was an implosion. The Arizona Cardinals outscored the 49ers 11-0 in the fourth quarter and pulled off a stunning 24-23 upset.

The 49ers lost kicker Jake Moody to an injury while attempting a tackle in the first half, which led to them attempting a 45-yard field goal on fourth-and-23 in the fourth quarter to try. San Francisco failed to score first there and not feeling comfortable attempting the field goal ended up being costly.

That wasn't the reason the 49ers lost, but it didn't help. And with the loss, the 49ers find themselves in a 2-3 hole to start the season. Nobody expected this from one of this season's Super Bowl favorites.

The 49ers are off to a slow start this season

The 49ers have dealt with numerous injuries this season, including running back Christian McCaffrey, who did not play this season.

Jordan Mason was a very good replacement, but he had a crucial mistake on Sunday. With the 49ers in the red zone and leading 23-21, Mason knocked the ball down on first-and-goal and the Cardinals rallied. Up until that point, it seemed like the 49ers would find a way to win. When Arizona took possession of the ball, the idea of ​​a surprise loss for the 49ers arose.

After that, the Cardinals drove downfield and ate up the clock. Kyler Murray completed a desperation pass to Marvin Harrison Jr. on the fourth and fifth to keep the drive alive. The Cardinals scored a field goal with 1:37 left to take the lead. The 49ers couldn't answer after that and the game was over.

This is how the season is going for the 49ers. They weren't terrible. They just weren't good enough to get wins in most cases.

The 49ers lose a late lead

When Moody was injured on a kickoff in the second quarter, it greatly changed the 49ers' decision-making. They saw punter Mitch Wishnowsky make a 26-yard field goal, but they wouldn't try anything much longer. So when the Cardinals took a one-point lead with 1:37 to play, the 49ers found themselves in the unusual situation of feeling like they had to score a touchdown to win. They couldn't let their punter make the game-winning field goal.

San Francisco didn't come close. A pass from Brock Purdy ended up in the air when it was hit and intercepted by Kyzir White. The 49ers couldn't even get past midfield with the game on the line.

During the fourth quarter, Fox showed the graphic that the 49ers were 38-0 in the regular season under Kyle Shanahan when leading by 10 or more points in the fourth quarter. This series ended on Sunday. The 49ers scored a TD on a blocked field goal and still couldn't beat an Arizona team that entered the game 1-3. Injuries or not, that's a bad sign.

The 49ers will probably get it going. But no one expected them to be under .500 in October.