Guerrero had worked with Fielder in the Brewers system and Fielder had twice before called on Guerrero to pitch to him during the derby.
"It's always fun and I am always glad that he looks to me to be there with him," Guerrero told MiLB.com. "To be in a room with the best of the best in the game is an incredible moment for anybody."
Guerrero had a few moments over his own career. He started his career as a player himself. He played nine seasons in the minors. He made AAA, but not the majors.
He then went on to his career as a coach, serving with the Brewers as hitting coach at both AA and AAA for the organization.
Guerrero's career began in 1985, signed by the Blue Jays as a free agent out of his native Dominican Republic.
The Brewers also took Guerrero out of a baseball family. His father, Epy Guerrero, was a top Dominican baseball figure. His brother, Mike Guerrero, would later be signed by the Brewers and go on to his own long playing and coaching career.
Sandy Guerrero started with the Blue Jays in the rookie Gulf Coast League. He played there two seasons, hitting .288 his second year.
He moved to the Brewers system mid-1986 and played at single-A Stockton. He played an abbreviated 1987 and then returned for a full season at Stockton in 1988. He hit .278, with 79 RBI and 23 stolen bases.
He arrived at AA El Paso for 1989. He hit .270, with 11 home runs that year. He returned there for 1990 and hit .248.
Guerrero made AAA Denver in 1991. He hit .282 in 73 games. He got into 76 more games there in 1992. He also saw nine games back at El Paso.
His time at El Paso that year also saw him play with his brother, Mike. The El Paso Times spoke with both that April, including one seeing the other move up.
"Sure, it'd be tough to see one of us go and the other to stay," Mike Guerrero told The Times. "But, I'd be happy, very happy, for him."
Sandy Guerrero, however, never saw the majors. That season in 1992 proved his last in the minors.
Guerrero soon started with the Brewers as a coach. In 2003, he served as a coach with AA Huntsville and stayed there through 2008. He coached Fielder at Huntsville in 2004.
He served as coach at AAA Nashville from 2009 to 2011, then returned to AA, where he continued in 2018.
After Fielder's 2012 Derby win, Guerrero explained to ESPN how the win happened.
"He just got into a flow with me right away," Guerrero told ESPN. "We just got that rhythm going together. I don't know if you noticed, but we did it the same every time: Take one pitch, take two pitches and here we go -- BOOM."
- El Paso Times, April 12, 1992: Baseball is a family affair for El Paso's Guerrero brothers
- ESPN.com, July 9, 2012: Prince now Derby royalty
- MiLB.com, July 11, 2015: Guerrero to pitch to Prince Fielder during All-Star Home Run Derby Monday
Made the Majors:1,116-36.8%
Never Made Majors:1,921-63.2%-X
5+ Seasons in the Majors: 466
10+ Seasons in the Minors:276