"He had a book there that had more stats about the Atlanta Braves than I've heard in 20 years," Leyland said. "He was accurate, too. He knew all their prospects. Very thorough."
The guest manager idea first came up last year, when Leyland offered the opportunity at a charity dinner he was attending. The day went so well, and the offer raised enough money, that the Tigers offered up something similar this winter.
Nagengast, a part-owner in a family business who grew up in the Detroit area, bid $10,000 for the package at a fund-raising dinner during the weekend of TigerFest, with the proceeds going to the Detroit Tigers Foundation.
"When it came up, I said, 'I've got to go after this,'" Nagengast said.
His managerial experience was limited to youth softball, coaching his daughters on a team in an East Grand Rapids recreation league. But his Tigers ties, of course, run deep.
"It's nice to meet somebody else who's interested in doing your job, a fan that watches you, guys that figure out or second-guesses you when they have a chance," Leyland said. "Somebody that knows baseball and asks questions, I think it's great. I don't really have any problems with people like that second-guessing.
"The Tiger fans know the game. They're not just there clapping, cheering. They know what goes on. They watch."
In this case, Nagengast took his knowledge into high gear, studying up on the Braves as much as he could so he could talk strategy. As much as he valued the experience, he seemed to love the conversation about baseball, too.
There were limits to what he could do in terms of game management, of course. But he had a little say on the lineup before he had the privilege of taking it out to home plate and exchanging it with Braves skipper Bobby Cox.
"The only thing is when I was at auction in January, I sat next to Marcus Thames that night," Nagengast said. "I was joking around with Marcus and I said, 'If I win this auction to manage, I'll do my best to get you in.' Then after the event, I went up and introduced myself to Jim and I said, 'Jim, do you think we can do this?' And he said, 'I think we can work that out.'
"So when I came in this morning, Marcus was in the lineup."
Not only was Thames in the lineup, but with Magglio Ordonez having a day off, he was batting cleanup.
Once they took the field, Nagengast sat next to Leyland, talked baseball and made some moves. He inserted slugging prospect Jeff Larish into the game as a reserve to get a look. He used closer Todd Jones in the ninth inning as scheduled. And before rain washed out the bottom of the ninth, he had his late-game strategy ready with Mike Hessman available as a pinch-hitter.
The players got into it, too.
"I asked him if I made the team," Dontrelle Willis said with a smile after tossing three scoreless innings. "He said yes. I appreciated it."
The reception Nagengast received actually surprised him.
"It was a great day," Nagengast said. "All the Tigers, not one jerk, everybody was nice and accommodating. I'm so glad I did it.
"I was surprised. They were all great. Probably seven or eight of them really went out of their way to explain things to me. Coming in, I didn't want to impose, but I felt very comfortable the whole game. It was wonderful."
The Tigers will double up on the concept with a pair of guest managers sharing duties on Sunday, when they're back home to host the Pirates.
Nagengast has a few more days to vacation in Florida before he returns to snowy Michigan. But for all his preparation for this one day, he's not considering a career change.
"Nah," he said. "I think these guys work too hard."