Credit: Matt Cashore-US PRESSWIRE

Well, that didn’t take long.  The San Francisco 49ers suffered their first major injury of the 2012 off-season with rookie outside linebacker Darius Fleming suffering a torn ACL.  Fleming, a fifth-round draft pick from Notre Dame, injured his ACL on the first day of the 49ers rookie minicamp during a non-contact drill.  The linebacker continued participating in drills after suffering the injury but he eventually had to leave and did not return.  The day before the injury, Fleming signed a four-year, $2.264 million contract.

Fleming did not tear any other ligaments other than the ACL, which means the recovery process should be smooth.   The real problem now for the 49ers is a lack of depth at outside linebacker.  While Fleming was mostly going to be a backup at outside linebacker and used mainly on special teams, the 49ers have only four other OLB’s on the roster: Ahmad Brooks, Aldon Smith, Parys Haralson and seventh-round draft pick Cam Johnson.  Even though Johnson is a seventh-round pick, he could have a big impact and fill in well for Fleming as a backup.  Fleming is expected to miss all of the 2012 season.

Johnson was expected to go as high as the second-round in the recent draft, but he slipped all the way to the 237^th overall pick.  One big reason was concern over Johnson’s health.  He has a sickle cell trait that was diagnosed last summer but he was still able to play in the University of Virginia’s 12 of 13 games this past season.  Johnson, who stands in at 6-foot-4, 270 pounds, now has a really great chance of making the 49ers final roster with the injury to Fleming.

Another option for the 49ers would be to bring in an unsigned veteran at outside linebacker.  There are not many options on the free agent list at OLB, but veterans like Rocky McIntosh (last season w/ Redskins) or E.J. Henderson (last season w/ Vikings) would add depth and experience to the 49ers’ roster.

This is the second year in a row the 49ers have had a rookie lost to an injury for the whole year.  Seventh-round pick and cornerback Curtis Holcomb tore his Achilles on the first day of training camp last year and missed the 2011 season.

Here is an inside look at Fleming:

Notes:

Won a state championship at Chicago Catholic League power St. Rita. Committed to then-head coach Charlie Weis and the Fighting Irish and recorded 24 tackles and 21⁄2 for loss (all sacks) in 13 games (three starts at outside linebacker) in 2008. Started 7-of-11 games in ’09 — five at defensive end, two at the “Sam” LB spot — and posted 30-12-3 with one forced fumble. Did not play against Washington (hamstring). Started all 13 games at OLB in N.D.’s 3-4 scheme in ’10, when he produced 49-11-6 with four pass breakups and one interception. In ’11, he recorded 55-7-3 1⁄2 with three pass breakups, one interception, one forced fumble and one blocked kick in 13 starts — 12 starts at OLB and one at defensive tackle. Has had three surgeries on his left shoulder. Cramped during 40s at Combine.

Positives:

Quick off the snap. Flashes edge-rushing ability and closing burst. Good arm length and upper-body strength. Nice knee bend and lateral movement. Shows flexibility and body control to drop in zones. Good tackler. Disciplined. Has worked from a two- and three-point stance and played in even and odd fronts. Moved cleanly through bags in Combine drills. Outstanding personal and football character — smart and well respected.

Negatives:

Lacks ideal height. Shows some tightness in his hips. Needs to develop counter moves. Average base strength. Gets outmuscled or swallowed up at the point of attack — not a stack-and-shed anchor. Has man-cover limitations. Ordinary production and playmaking impact. Has had multiple shoulder surgeries and durability is a concern.

Summary:

Undersized, athletic, tweener with strong intangibles. Played hurt and did not dominate in college. Developmental prospect capable of becoming a better pro than college player if used properly in pass-rush specialist role.