Marshawn Lynch, Ben Roethlisberger lead Sunday’s list of NFL injuries

Yesterday’s NFL action featured a relatively short list of key injuries, but one in particular carries a potentially huge impact on the balance of power in the AFC: Pittsburgh Steelers quarterback Ben Roethlisberger’s knee sprain.

If early reports are correct, Steelers fans should be able to breathe a huge sigh of relief. It appears Roethlisberger has sustained a sprained medial collateral ligament (MCL) and bone bruise of the left knee, but he has avoided further damage to other structures. Roethlisberger suffered the injury in the third quarter of Sunday’s win over the Rams, when he was struck from the outside of the joint by St. Louis safety Mark Barron. The Pittsburgh QB was carted off the field, and there was considerable speculation about exactly how much damage he took.

Most typically, a direct blow to the outside of the knee would include damage to the medial collateral ligament, the structure that runs along the inside of the joint -- connecting the femur (thigh bone) to the shin bone (tibia) -- and keeps the knee from rotating sideways. Without damage to other structures of the knee, an MCL sprain alone generally does not need surgery, and his recovery would depend on the grade of the sprain.

By definition, sprains involve some degree of tearing of the ligaments: a Grade 1 sprain, for example, involves only a small amount of ligament fiber damage, whereas a Grade 3 sprain translates to a complete tear. The expected timetable for recovery for MCL sprains generally are 1-2 weeks for a Grade 1 sprain, 3-6 weeks for a Grade 2 sprain and up to 2-3 months for a Grade 3 sprain.

When Roethlisberger does return -- early indications were that the Steelers were anticipating a 4-6 week recovery period consistent with a Grade 2 sprain -- he will almost certainly require a brace on the left knee, which may affect his mobility.

The x-factor in his recovery time is the bone bruise, which could add to the timetable if it doesn’t heal as quickly as the ligament. For now, though, the team is undoubtedly relieved that it is just an MCL sprain rather than other alternatives. They’ll turn to Michael Vick at QB this Thursday night against Baltimore and into the remainder of October.

Seahawks running back Marshawn Lynch, who was questionable to play on Sunday in the first place due to a calf injury, left Seattle’s 26-0 win over Chicago with a hamstring injury and didn’t return to action.

The durable Lynch, who hasn’t missed a game since being traded to Seattle from Buffalo in 2011, will have the advantage of an extra day of recovery this week, as the Seahawks don’t play again until next Monday night against Detroit. Hamstring injuries are notoriously slow to heal and even more notorious for being prone to re-injury if tested before an athlete has fully recovered. Meaning: Lynch’s status may come down to pregame warmups a week from tonight.

Second-year receiver Sammy Watkins left the Bills’ thrashing of the Dolphins yesterday with an injured calf, just about the only sour note for his team on the day. Watkins suffered the strain early in the first half, after having hauled in a 39-yard pass from Tyrod Taylor, and left for the training room shortly thereafter.

Like hamstring injuries, calf strains are slow to heal and easy to aggravate, so Watkins is unlikely to jog or run early in the week. If he remains limited in practice by early next weekend, we should have a good idea of whether he’ll be able to take the field against the Giants on Sunday.

It was an abysmal day overall for the San Francisco 49ers, getting blown out at the hands of the Arizona Cardinals stings worse due tight end Vernon Davis’ knee injury. Davis missed most of the second half with the injury. He remained on the bench and did not require any immediate testing.

The 49ers haven’t provided any updates on the severity of Davis’ injury, and although to this point it doesn’t appear to be serious, keep an eye on his practice status this week as San Francisco attempts to rebound against Green Bay next Sunday.

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