"We wish him the best of luck there," Andy Reid said Wednesday. "It's an opportunity for him to make their roster and have an opportunity to play."
Johnson was on the Chiefs practice squad, which means any team is eligible to sign him (and pay for him for at least three weeks). That's how the practice squad works and that's why it can be a risk to put players there.
Johnson was the Chiefs fourth round pick in the 2013 NFL Draft. Injuries slowed down his progress in his first year and he was never quite able to catch on from there. He was cut from the Chiefs before the season and placed on the practice squad.
This is good news for Johnson as a player because it means he is now on someone's active roster, rather than the practice squad. For the Chiefs, it means their hopes of developing him are now gone.
For you Bengals fans out there, Johnson came in as a run-stopping inside linebacker. He will need to improve there as well as his pass coverage, which could come from game experience. He was credited with six games last year.