Sean McManus Guenther was a seventh round selection of the Miami Marlins in 2017, and has already played at four levels of minor league ball.
Throughout the 2018/2019 offseason, Marlin Maniac will devote one article each for every player who appeared in the Miami Marlins system for the 2018 season. Every. Single. Player. This is Part 174 of 286. For the first 100, click here.
Sean Guenther is a 5’11”, 194 lb. left-handed pitcher from Atlanta, Georgia. Born on December 29th, 1995, he played three seasons for Notre Dame starting in 2015. Over 182 innings of Division I ball, he was 6-14 with a 3.50 ERA for the Fighting Irish, with 153 strikeouts and a 1.33 WHIP. In 2017, he was picked with the 209th overall selection.
Players selected 209th overall have a 14 percent success rate at eventually reaching the major leagues. The group is led by Rich Hill (2001, Anaheim Angels, 12.4 career WAR) and Jon Niese (2005, New York Mets, 8.4 WAR). If Guenther is destined to reach the level, it should be sometime around 2021. You can follow him on Twitter @theGUENshow. Here’s Guenther pitching for the Irish, a month before he was drafted, courtesy of FanGraphs.
Guenther signed with the Miami Marlins for a $198,500 bonus, and joined the rookie-level, Florida-based GCL Marlins, in the Gulf Coast League on July 3rd. After giving up just five hits and whiffing 11 in as many innings, he was pushed up to the short-season-A Batavia Muckdogs, in the New York-Penn League on July 17th.
Guenther made nine rotation starts for the Muckdogs through 2017, going 1-4 with a 3.83 ERA. He struck out 33 in 40 innings, with a 1.18 WHIP. In his best start at the slightly higher level, Guenther earned no-decision in a 2-1 loss to the Vermont Lake Monsters, striking out three and allowing only two hits and zero walks in five innings. Here’s Guenther, speaking for himself courtesy of 6-4-3 DP Baseball.
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Guenther was aggressively promoted to start 2018, up two levels to the high-A Jupiter Hammerheads in the Florida State League. Unfortunately, he wasn’t quite ready, and struggled to a 1.61 WHIP and 48 hits allowed in 31 2/3 innings. Although he only walked three batters over that time, he also only struck out 13 batters, going 0-1 with a 4.83 ERA. On May 14th, he was placed on the disabled list.
After a rehab assignment in GCL in late-June, Guenther joined the single-A Greensboro Grasshoppers in the South Atlantic League on June 27th. Much more effective at the higher level, Guenther started eight games and made five trips out of the bullpen. He dropped his WHIP to 1.28 and went 4-3 with a 4.45 ERA. On August 20th, he earned a complete game, seven-inning shutout victory. He earned an 85 GameScore for his efforts, striking out seven and allowing only two hits in a 2-0 win against the Kannapolis Intimidators.
Guenther doesn’t have overpowering stuff, and he’s only struck out 99 in 138 innings of work since turning professional. What he does have is ridiculous control. He’s walked 13 over that same time for a BB/9 rate of 0.84, thrown three wild pitches, and has never balked or hit a batter. The Miami Marlins currently have him rostered with the Clinton LumberKings in the single-A Midwest League.
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