BBAO: John Sullivan's knee

We're Black and Blue All Over:

It's not unusual for an NFL player to undergo offseason knee surgery, as Minnesota Vikings center John Sullivan did last week, via Tom Pelissero of 1500ESPN.com.

The type of surgery Sullivan had is not typical, however. A surgeon in the office of Dr. James Andrews performed a microfracture procedure on his left knee that probably will curtail most offseason work. The surgery typically includes drilling small holes in the bone to help spur the healing, or limit the damage of, injured cartilage, and has been associated with serious long-term conditions.

Pelissero reports that Sullivan's injury is not as severe as it could have been, which makes sense considering he did not miss a snap in 2012 on the way to the best season of his career. As always, we'll take our cues on this from the Vikings' offseason action or inaction. If they sign or draft a center, you'll know they are concerned about Sullivan's status. If not, you can assume they think he'll be ready for the start of training camp.

Continuing around the NFC North: