We won't call the preseason entirely meaningful, but his first game reps with his new team were important. He made the most of them on Saturday in Denver.
With the quarterback competition solved, eyes were on Charles with his first carry, a seven-yard tote on second down. The running back made a few cuts on subsequent runs that demonstrated his knee could handle at least a four-carry workload, which was worth 27 yards rushing on Saturday.
The play prior to his first carry also served as evidence that his addition might end up being quite worthwhile for Denver.
As quarterback Trevor Siemian dropped to pass, guard Max Garcia was soundly beaten by Green Bay defensive tackle Mike Daniels. Charles slid to his left into the path of Daniels and went low, cutting Daniels' legs to save Trevor Siemian from getting drilled from the blind side. It wasn't the lone instance in which Charles displayed above-average pass-blocking ability.
There's also the option of targeting Charles out of the backfield. He caught two passes for 15 yards, but also looked green in Denver's offense, running a route into the flat early and failing to turn around to look for the ball before it was already by him for an incompletion.
Charles doesn't look quite like the burner he once was in Kansas City, but he still has above-average speed. Head coach Vance Joseph called him "explosive" during a halftime interview. After the game, NFL Network's James Palmer reported Charles had officially made the 53-man roster.
All Charles needed to do was prove he could make it through a game. The running back did more than enough in 15 plays.