Matthew Olson Guerrier (born August 2, 1978) is an American former professional baseball relief pitcher.

He played in Major League Baseball (MLB) for the Minnesota Twins, Los Angeles Dodgers and Chicago Cubs.

A native of Cleveland, Ohio, Guerrier attended Shaker Heights High School.

[3] He pitched in the White Sox minor league system through 2001, reaching Triple-A with the Charlotte Knights.

[6] Guerrier made his Major League debut on June 17, 2004 against the Montreal Expos as the starting pitcher.

[6] In 2008, the Twins lost primary setup pitcher Pat Neshek to injury early in the season and Guerrier took over part of that role for a short time.

[13] He was placed on the 60-day disabled list and did not rejoin the Dodgers until the last week of August, ending his string of five straight seasons with at least 70 games pitched.

[6] Guerrier pitched in 34 games with the Dodgers in 2013, posting a 2–3 record with a 4.80 ERA before he was designated for assignment on June 30.