Career
He is the former pitching coach for the Boston Red Sox. He played for the Milwaukee Brewers from 1986–1988. Nieves was signed by the Milwaukee Brewers, with a $115,000 signing bonus, after he went 19-1 with a 1.05 European Research Area during his senior season at the Avon Old Farms school in Connecticut.
On April 15, 1987, against the Baltimore Orioles, became the second-youngest player in major league history to throw a no-hitter, and so far the only Milwaukee Brewer to do southern
Nieves" no-hitter became the first ever thrown by a Puerto Rican in Major League Baseball. After playing for the Brewers from 1986 to 1988, he suffered a career-ending arm injury.
He worked as a minor league pitching instructor for the New York Yankees (1992–1996) and the White Sox (1999–2007) before joining the Chicago White Sox Major League staff as the bullpen coach serving for the five seasons. He was mentored by Don Cooper, first when Cooper was the White Sox" roving coordinator in their minor league hierarchy, and later when Cooper became the pitching coach of the Sox.
They became really close, adapting similar pitching styles and was named as "Cooper"s right-hand man".
He was named Boston"s 2013 pitching coach on November 7, 2012. He brought over Cooper"s style of pitching to the Red Sox organization. After earning the second highest team European Research Area (486) to start the 2015 season, Nieves was dismissed by the Boston Red Sox on May 7, 2015.