Matt Mantei, a right-handed relief pitcher, made his debut in Major League Baseball with the Florida Marlins. Born on July 7, 1973, in Tampa, Florida, Mantei's journey to the majors began when he was drafted by the Seattle Mariners in the 25th round of the 1991 MLB Draft. However, it was with the Marlins that he first stepped onto the major league mound.

Mantei's early career with the Marlins was marked by his powerful fastball, which often reached the upper 90s, making him a formidable presence in the bullpen. His rookie season in 1995 saw him appear in 12 games, where he began to establish himself as a reliable reliever. Over the next few years, Mantei's role with the Marlins expanded, and by 1999, he had become the team's closer. That year, he recorded 10 saves for the Marlins before being traded mid-season to the Arizona Diamondbacks.

The trade to Arizona proved to be a turning point for Mantei. With the Diamondbacks, he continued to excel as a closer, finishing the 1999 season with a total of 32 saves, 22 of which came after joining Arizona. His performance helped solidify the Diamondbacks' bullpen, and he quickly became a fan favorite due to his fiery demeanor and ability to strike out batters in critical situations.

Injuries, however, began to plague Mantei's career. Despite his talent, he faced several setbacks, including elbow issues that required surgery. These injuries limited his playing time and effectiveness on the mound. Nevertheless, Mantei persevered and continued to contribute to the Diamondbacks when healthy. In 2001, he was part of the Diamondbacks team that won the World Series, although his participation was limited due to injuries.

Mantei's tenure with the Diamondbacks lasted until 2004, after which he signed with the Boston Red Sox. His time in Boston was brief, as injuries continued to hamper his ability to perform consistently. He appeared in only 34 games for the Red Sox during the 2005 season, recording a 6.49 ERA.

Following his stint with the Red Sox, Mantei attempted a comeback with the Detroit Tigers in 2006. Unfortunately, his persistent injury problems led to his release before the season began, effectively ending his major league career.

Throughout his career, Mantei was known for his high strikeout rates and his ability to close games under pressure. Despite the challenges he faced with injuries, he left a lasting impression on the teams he played for and the fans who watched him pitch. His career statistics include 93 saves and 396 strikeouts over 322 innings pitched, reflecting his role as a dominant reliever when healthy.