H/T Nick Andron
Per Sando:
The severity of the injury was not immediately known, but trainers helped Spencer to the cart after the center tried to take one step. Spencer did not attempt to put weight on his left leg from that point forward.
Mike will (or has already) be on with Brock and Salk on 710ESPN with perhaps more details. Since John is off covering camp, I'll be sure to update this post with more information as it comes in.
UPDATE: Per Danny O'Neil at the Seattle Times
Center Chris Spencer suffered an ankle injury during the Friday morning practice. Coach Jim Mora said it does not appear to be serious and said the initial indication is that it was not a high ankle sprain.
Good news if it isn't the dreaded high-ankle sprain.