MESA, Ariz. -- Michigan football head coach Jim Harbaugh was in A's camp as a "special guest instructor" to good friend Bob Melvin on Saturday, fully dressed for the part in preparation for a seven-inning stint as first-base coach during Oakland's 8-7 walk-off win over the Angels.
"I only travel to see the best," said Harbaugh, grinning wide after the victory.
"He had as much fun as anyone here," said Melvin. "If we had gone 15 [innings], he probably would've stayed out there. He just loves the competition."
Upon his early-morning arrival, Harbaugh requested two things: No. 4, and stirrups. He left with both, and even had his favorite player, Coco Crisp, sign his cap, helmet and jersey.
"How does it get any better than this?" said Harbaugh. "It's a great day for baseball, and just to be able to put on the uniform ... I haven't been in a baseball uniform since American Legion ball."
Melvin has two years on Harbaugh, but they played on the same American Legion team in the Bay Area, forming a friendship that has lasted through the years. It strengthened in 2011, when Melvin returned home to manage the A's, and Harbaugh moved on from Stanford to coach the 49ers.
Melvin was a constant on the sidelines, standing just 15 feet away from Harbaugh during a rather turbulent 49ers season that ended with Harbaugh's dismissal last year. The very next day, Harbaugh was recruiting in Michigan and he's had very little time for anything else since.
But he never forgot about Melvin's invitation to Arizona.
"I wanted to give him this experience because he brought me in, and I got to watch some games down there with him, watch his meetings and how his coaches prepare," said Melvin.
Melvin said he particularly admires the way in which Harbaugh address his teams, admitting he's even stolen a bit of Harbaugh's material from time to time.
On Saturday, it was Harbaugh borrowing a line -- from Ernie Banks: "It's a beautiful day for baseball," he said. "Let's play two."
"He's an inspiration just walking out here," Melvin said. "He's got that air about him. He's always been quite the competitor and everyone knows that. A winner. And whenever you can have guys like that around, guys benefit from it. Plus you don't find too many guys who want to get in uniform and go out there and interact with the guys during the workout."
The respect is obviously mutual between these old friends.
"He's the best," Harbaugh said of Melvin. "Good friend. ... He's so detail-oriented, so organized. He's got a great relationship with his players. He loves his players, and I respect that. Just probably the best thing is when we talk and text during the season, and I have something to bounce off him, he's always very responsive and very helpful."
Harbaugh's first exposure to baseball came at an early age. His father, Jack, grew up with Detroit outfielder Gates Brown, so the family was a mainstay at Tigers games. On the field, though, Harbaugh considered himself "mediocre."
"I was doing OK. I was about a .417 hitter in high school, and then my dad came home with the 'Charlie Lau Theory of Hitting,' and after that I could not get the ball out of the infield."
Jane Lee is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.