He's certainly faster than I am.
This won't at all indicate whether Spence is ready to run down Giovani Bernard in the open field, or if he can carry Dennis Pitta down the seam, but he doesn't appear to have a hitch in his gait or anything either.
Spence's knee injury wrecked his career to this point, and still has a bit to show whether he can make this team. Several linebackers have been added to the Steelers since his injury, including the 15th overall pick in this draft, Ryan Shazier (who gets a brief cameo at the end of the video). The fact he made it back on the field is certainly one version of success, the question will be whether he can make it all the way back and contribute to this team this year.