The injury Ryan Williams suffered during his second NFL exhibition game was relatively unusual for football players.
Notable NFC West Injury Situations
A torn patella tendon ended Williams' rookie season before it officially began.
The running back expects to return for training camp and the 2012 regular season. Cadillac Williams and Earnest Graham returned from similar injuries, but each situation is different. The Cardinals cannot know how the knee will respond. No one can.
Cadillac Williams returned, only to injure his other knee. Suffering a second injury so quickly complicated comparisons to other running backs returning from a single torn patella.
Ryan Williams is not yet even 22 years old, however.
"He has youth on his side, for sure," ESPN injury expert Stephania Bell said Thursday. "What you worry about is, it takes a lot to get any kind of explosiveness or power back. You're not talking about strength, but quickness."
Williams, a second-round choice from Virginia Tech, impressed the Cardinals with his ability to change directions without losing much speed.
"It is reasonable he could be back when the season starts," Bell said, "but will he really be back? That is going to remain to be seen and like these guys coming off ACL surgeries, it may take a while to see what his max is that he can return to."
The Cardinals need Williams in part because their primary back, Beanie Wells, has struggled with injuries, fighting through knee trouble last season after undergoing surgery.
Four additional injury situations to monitor, one per NFC West team, as the offseason continues:
Arizona: Kevin Kolb, quarterback. Concussion problems have sidelined Kolb each of the past two seasons. Symptoms lingered last season. Quarterbacks are going to take hits unexpectedly, sometimes to the head. Can Kolb stay on the field?
Seattle: Sidney Rice, receiver. Rice has undergone surgery on each shoulder. One surgery repaired damage suffered during training camp. The other repaired damage incurred during college. The hope is healthier shoulders will allow Rice to improve strength throughout his upper body.
San Francisco: Josh Morgan, receiver. The 49ers were relatively healthy last season, but losing Morgan to a broken ankle cost them as the season progressed, particularly late. Morgan is without a contract for 2012. He has been working out at the 49ers' team facility. Getting him back would help the offense.
St. Louis: Rodger Saffold, pectoral. The Rams had injuries throughout their roster, especially at cornerback. Saffold's ability to play four positions on the line, including left tackle, makes him more valuable than members of the secondary. Saffold has said he hopes to be ready by April or May, according to Howard Balzer. He suffered a torn pectoral while lifting weights in mid-November.