When former coach Tony Dungy visited Indianapolis Colts training camp Aug. 15, Andrew Luck gave him no inclination of the bombshell to come.

Though Luck wasn't working with the rest of the team at Westfield's Grand Park, "he was working like a maniac," Dungy told radio host Dan Patrick on Tuesday.

"He was jumping on boxes, agility drills and doing his pass sets, throwing balls 1,000 mph," Dungy added. "I talked to him for five minutes, and you could see the frustration that he wasn’t out there, but I left my five minutes thinking, 'Maybe not Week 1, but Week 2, Week 3, he’ll definitely be there.'"

Colts legend Peyton Manning also attended that practice, and Dungy said Manning came away with the same impression.

"Peyton talked to him for about 30 minutes, and they’re talking about recovering from injury and all the things Peyton went through," Dungy said. "He came away with the same thing, that this guy is so close to being there."

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If Dungy was coach in this situation, how would he have approached it?

Dungy said he would have said: "'Hey let’s make sure this isn’t a quick emotional reaction. I know your frustration."

Dungy would have asked Luck about the possibility of playing at less than 100%.

"If you don’t think you can, and you don’t want to play at that level, or there is this pain management you’re dealing with, I understand that," Dungy said. "We’re going to support you. Give me four or five days to think about this. Let’s see where it goes.'"

The Colts have said Luck approached them about retiring early last week, and that they had discussions over several days before Luck's announcement Saturday night.

Dungy said he believes the suddenness of the announcement, and that it came so close to the regular season, is what angered some fans.

"It’s a little more sudden with Andrew, in that he went to training camp," Dungy said. "I think that’s what got people thrown off. If he had said this a day before coming to camp, maybe people would have understood and taken it a little better."

While it played out as a spur-of-the-moment move, Dungy thinks Luck may have been contemplating it for a while.

"Maybe it started with the shoulder injury (that cost Luck his 2017 season)," Dungy said. "This was not, ‘I woke up yesterday and decided I’m going to retire.’"

It reminded Dungy of a conversation he had with Barry Sanders before a Tampa Bay-Detroit game.

"He told me, ‘One of these days you’re going to look up, and I’m not going to be there.’ … It was something he had been contemplating," the former Buccaneers coach recalled. "Money didn’t mean anything to him. He was nearing Jim Brown’s record. That didn’t mean anything. It was just time to go. The joy of the game had left, and he was gone."