The Reds have not confirmed the report.
A right-handed pitcher, Stephenson was the 27th overall selection in the 2011 First-Year Player Draft out of Alhambra High School in Martinez, Calif. During his senior season, he was 8-2 with a 1.19 ERA in 76 2/3 innings and tossed two no-hitters.
The deadline for clubs to sign 2011 Draft picks is midnight ET on Tuesday. Negotiations between Stephenson and the club have yet to begin in earnest, but he underwent a physical to get it out of the way before the deadline. There is an alternate option for Stephenson should he not sign with Cincinnati. He has already committed to play college baseball for the University of Washington.