HOUSTON -- Indianapolis Colts quarterback Anthony Richardson wasn't on the field for a late-third-quarter play in a game in which his team trailed by two scores and later lost.

Curiously, Richardson was on the sideline not because he was hurt but, rather, because he was exhausted.

The second-year quarterback exited the game after scrambling around furiously on the previous two plays against the Houston Texans' defense. On a second-and-goal play from the Houston 23-yard line, Richardson shook off a would-be sack from defensive tackle Folorunso Fatukasi before turning up the field and looking for a target. Richardson ended up keeping the ball and was ultimately tackled by linebacker Jake Hansen for no gain.

Richardson got up slowly and headed to the nearby Colts sideline, tapping his helmet while in route. On the sideline, he immediately took a knee.

"I was tired," he said. "I ain't gonna lie. That was a lot of running right there. I didn't think I was going to be able to go that next play, so I just told [Colts coach] Shane [Steichen] I just needed a break right there."

Richardson's departure from the game initially raised questions about whether he had sustained an injury. Earlier in the game, he took a hit that impacted his left hand and was seen flexing it on the sideline. But athletic trainers who checked on him did not appear to be treating an injury and seemed satisfied that he was fine.

"He needed a breather," Steichen said. "He ran three times in a row and it was third and long, so we were going to hand the ball off."

Backup quarterback Joe Flacco entered the game and did, in fact, hand off to running back Jonathan Taylor on a third-and-goal from the 23. Taylor gained 5 yards, and the Colts settled for a 37-yard field goal, trimming Houston's lead to 20-13. The Texans ultimately won 23-20.

The strange string of events is only going to intensify the discourse around Richardson, whose season-long struggles have been a weekly challenge for the Colts to navigate. The fourth pick in the 2023 draft, Richardson has completed 44.4% of his pass attempts on the season after Sunday's 10-for-32, 175-yard effort.

Sunday's pivotal AFC South matchup -- a win would have given the Colts a share of the division lead with Houston -- instead became another referendum on Richardson's future with Indianapolis.

Richardson's skill players let him down repeatedly in the game, with running back Tyler Goodson dropping a perfect touchdown pass and a Michael Pittman Jr. penalty negating another would-be Richardson touchdown throw. Richardson also was pressured on 17 of his 32 dropbacks in the game, which suggests some protection issues.

But the conversation is likely to center on the performance of Richardson, despite his career-long 69-yard touchdown pass to receiver Josh Downs.

After showing flashes of his significant talent in the four games he played in 2023 before suffering a season-ending shoulder injury, Richardson has arguably experienced regression in 2024. For his part, Richardson rejected that narrative.

"I feel like I'm a great passer," he said. "I've been playing quarterback pretty much my whole life. I'm just a different quarterback from everybody else, so people are going to try to point out that I'm not as efficient as everybody else. But it's cool to me. I run the ball way better than every other quarterback. Probably not Lamar [Jackson], but [better] than most quarterbacks. So, I take advantage of my opportunities."

Richardson did have 45 rushing yards on six carries Sunday, but only two of his rushes were designed runs. That paled in comparison to the seven he had in a win over the Miami Dolphins last week.

So, what's next for Richardson? The Colts have resisted the idea of starting Flacco since Richardson returned from a two-game absence because of an oblique injury. But questions about Richardson are not likely to subside.

"We keep working through the process," Steichen said. "It's a process. We keep grinding through it. We do it together. It's a team game. We grind through those things and we get it figured out."