McGuff, a Cincinnati, Ohio native, was drafted in the 36th round of the 2016 MLB Draft by the Minnesota Twins from Morehead State University. From 2016-17, McGuff split time between the GCL Twins, Elizabethton and Cedar Rapids. In 49 appearances in affiliated baseball, he went 5-2 with a 2.40 ERA and 12 saves. He pitched 82 1/3 innings and struck out 95 batters. In 2018, McGuff started the season with the Otters, going 3-1 with a 1.55 ERA in five starts, striking out 26 in 29.0 innings pitched. In July of 2018, McGuff signed with the Cincinnati Reds organization was assigned to the Dayton Dragons. With the Dragons, McGuff went 2-5 with a 4.09 ERA in 10 starts, striking out 35 in 50.2 innings pitched. McGuff played collegiately at Morehead State, helping the Golden Eagles to 2015 NCAA Louisville Regional appearance.