The 6-3, 280-pound Herron, a two-year starter for the University of Iowa, had been with Detroit throughout training camp and the preseason, following his signing as a free agent April 27.
Herron had 172 total tackles and 10 sacks for the Hawkeyes.
Earlier, as a prep, he won all-state and all-league honors in football while playing for Bolingbrook (Ill.) High School, playing both offensive tackle and defensive end. He also lettered in basketball and track, and was the conference shot put champion as a junior.
Herron joins linebacker Donte' Curry, fullback Chris Gall, G/T Ed Kehl and CB Hurley Tarver, signed to the practice squad on Monday.