The highest highs, the lowest lows, Prior has covered them all.
Today, Prior, 34, is back in uniform as a first-year Minor League pitching coordinator for the team after a year in the front office. He is in big league camp where there are actually three pitchers older than he -- Jason Lane, 38, Joaquin Benoit, 37, and Jose Valverde, 36.
Prior will head over to the Minor League side for prospect camp Thursday and then to Minor League camp in March, where he figures to share more than just instruction. He will share his story, the highs and lows, with hopes it might resonate with someone.
"I think as a player, anytime you can listen to someone talk to you coming from a place they've been, it's a little more tangible, a little more genuine," Prior said.
"And I think that because of the wide range of my career ... from the top to the bottom, hopefully I have some experience that I can relate to someone, personally or professionally. If I can, then all the better."
Prior was able to do amateur and professional scouting last year with the team but felt he didn't get a chance to touch the development side. This role will certainly give him that opportunity as he works with young pitchers in the system on a daily basis, rotating through Minor League affiliates once the season begins.
San Diego manager Bud Black said this new role fits Prior perfectly.
"When Mark decided to retire as a player and came on board, I could see a guy with a lot of potential in this game, no matter which direction he took," Black said. "I saw the work ethic, I saw him go out and scout, write reports, and we've had dialog about pitchers and players.
"He's going to bring a lot to us. He brings a great perspective as a guy who has been through a lot. He has a perspective that will be very useful for all of us, especially the players."
On Saturday, Prior and Lane, two former USC Trojans, were standing off to the side of one practice field talking pitching. Prior sounded energized afterward, especially after listening to Lane, the converted outfielder who is still trying to master the nuances of pitching.
"He's still really passionate about the game. He's still trying to learn the art of pitching. He's still trying to find his way," Prior said. "And the neat thing about it is there's no right way and no wrong way to go about it. He's doing it his way."