The Philadelphia Phillies have signed supplemental first-round draft pick Mitchell Gueller, according to Jim Callis of Baseball America. Gueller, a Washington High School right-handed pitcher, signed for the full $940,200 slot signing bonus recommended by the MLB office for the 54th overall draft pick.

Callis evaluates Gueller as a pitcher who has flashed three plus pitches, but also had late helium this year and climbed some boards because of that. ESPN's Keith Law agrees, writing Gueller "has a chance for three average or better pitches."

The Phillies have now signed both their first-round draft picks, the other being Lakewood High School pitcher Shane Watson.

• Twitter / jimcallisBA: ‪#Phillies‬ also land sandwich pick Mitchell Gueller for $940,200 (full value). Washington HS RHP had late helium, flashes 3 plus P. ‪#mlbdraft‬