Luck, who has missed most of the last three seasons with kidney and shoulder injuries, completed 8 of 10 passes for 90 yards and a touchdown on Saturday night as the Colts defeated the San Francisco 49ers 23-17 in Indianapolis.
"I feel great, my shoulder feels awesome, the best it's felt," Luck told reporters after the game. "I actually feel very good, strong, my shoulder felt alive. I was a little happier with where the ball went when I threw it. I keep feeling and seeing improvement. Keep working at it."
Luck, who turns 29 in September, has been brought along slowly this summer as he recovers from an October setback following a January 2017 shoulder surgery, which ultimately kept him out of the entire 2017 season.
In his preseason appearances, he hit on 20 of 32 passes for 204 yards with one touchdown and one interception. He's not expected to play Thursday in the Colts' final preseason game.
Saturday night's scoring toss came after he absorbed a big hit from San Francisco linebacker Dekoda Watson.
"To be honest, I forgot how fast guys in the league are," Luck said. "The guy from behind actually caught me by surprise. And it was a lesson again that in this league there's always someone behind you and you can't relax."
Colts head coach Frank Reich said, "Other than making sure he was good physically, I really didn't have very many questions. ... The process that he's going through, seeing him work every day, seeing his attitude, really had not too many doubts."
In six seasons, Luck has completed 59.2 percent of his passes for 19,078 yards and 132 touchdowns. He has also been sacked 156 times, long a concern in the wake of his past injuries.
Reich said Luck has "been perfect" in demonstrating when he should get rid of the ball or be aggressive when he has to.
"There's not one time he tried to get more than he should have and gone down, and appropriately went for it at the times that he could," Reich said. "I think he's handled that. Whatever determination he made in his mind about how he's going to adjust his play, I think he should feel good about where he's at."
--Field Level Media