Sean McManus Guenther (born December 29, 1995) is an American professional baseball pitcher for the Miami Marlins of Major League Baseball (MLB).
A native of Atlanta, Georgia, Guenther attended Marist School in Brookhaven, Georgia. He graduated from high school in 2014. Guenther committed to playing baseball for the Fighting Irish baseball team of the University of Notre Dame.
In his freshman season, Guenther was named a Louisville Slugger Freshman All-American and named to the ACC All-Freshman team as well as leading the Irish with five saves. In 2015, Guenther posted a 1–3 record with a 2.72 ERA and a 1.295 WHIP in his freshman season.
In his Sophomore season, Guenther posted a 3–5 record, 4.62 ERA, and a 1.369 WHIP with 11 starts and 15 total appearances in 2016.[1] After the 2016 season, Guenther played collegiate summer baseball for the Orleans Firebirds of the Cape Cod Baseball League.
In his junior year, Guenther posted a 2–6 record, a 2.64 ERA, 1.328 WHIP, and seven saves. After his junior year, Guenther was drafted by the Miami Marlins in the seventh round (209th Overall) of the 2017 MLB Draft.
To begin the 2021 season, Guenther was assigned to the Pensacola Blue Wahoos of Double-A South. In 17.2 innings with Pensacola, Guenther posted a 1–0 record with a 1.02 ERA and 28 strikeouts.
On June 8, Guenther was promoted to the Jacksonville Jumbo Shrimp of Triple-A East. On August 4, Guenther was called up by the Marlins and made his debut 2 days later. On April 7, 2022, Guenther underwent Tommy John surgery, ending his 2022 season before it began.
Sean Guenther has never divulged any information about his parents, he is a very private person who likes to keep his personal life away from media attention.