The former National Football League quarterback signed with the CFL's Saskatchewan Roughriders earlier this offseason but tore his hamstring during training camp practice.
Young, 34, was attempting a comeback after being out of football since 2014.
The 33-year-old was signed to a one-year contract with a team option for a second season.
Young's injury required at least four weeks of healing and rehab.
Young's pro career started off well as he earned a Pro Bowl selection and graced the cover of the popular Madden NFL video game after his rookie season. He is a former star with the University of Texas Longhorns and the NFL's Tennessee Titans. The Roughriders regular season begins Thursday and they opted to waive Young.
Johnson, a 5-foot-9, 189-pound defensive back, was released by the Als ahead of Saturday's roster deadline.