Matt Barkley's separated shoulder represented the exclamation point on the downward spiral that was the end of his 2012 season, and the injury may continue to plague him all the way into April's NFL draft.
Barkley's slide started in late October when the former Heisman favorite began to miss his targets and throw interceptions. Then, it all came crashing down during a loss to UCLA on Nov. 17—both figuratively and literally (h/t Mike Hiserman, Los Angeles Times):
Brett Hundley, a redshirt freshman, outplayed USC senior Matt Barkley. Hundley completed 22 of 30 passes for 234 yards and a touchdown and also ran for two touchdowns. Barkley completed 20 of 38 passes for 301 yards and three touchdowns with two interceptions before leaving the game with a couple of minutes to play after a crushing hit by UCLA linebacker Anthony Barr.
Following the game, CBS Los Angeles reported that Barkley suffered a separated throwing shoulder on the play. He did not throw a football the rest of the season, and according to Chris Wesseling of NFL.com, he will not throw at the NFL Scouting Combine, either.
Given the exact nature of his injury, that is not very surprising.
A shoulder "separation" implies disruption of the acromioclavicular joint (AC joint)—where the scapula, or shoulder blade, meets the clavicle, or collarbone. In contrast, a shoulder "dislocation" occurs when the humerus—the bone of the upper arm—is pulled out of the glenoid—a small empty pocket at the end of the scapula.
The scapula and clavicle are connected by three ligaments—one acromioclavicular (AC) ligament and two coracoclavicular (CC) ligaments. Like all ligaments, the AC and two CC ligaments stabilize and coordinate motion between the bones they connect. The AC ligament connects the acromion—a pointed extension of the scapula—to the end of the clavicle, and the CC ligaments connect the shaft of the clavicle to the coracoid process—a second pointed extension of the scapula.
Also like all ligaments, the AC and two CC ligaments can only handle so much stress. If the acromion and clavicle are forced apart sharply enough—by, say, being fallen on by a linebacker for example—one or more ligaments can tear, resulting in a shoulder separation.
There are six types of shoulder separations. A type I separation is minor and consists of only a partial AC ligament tear. Type II and type III separations are more serious. A type II is a complete tear of the AC ligament, while a type III represents complete tears of both the AC ligament as well as the CC ligaments.
Type IV through VI separations are extremely serious injuries where the bones are greatly displaced or muscle injury occurs on top of ligament tears. Fortunately, they are very rare and generally only occur with massive trauma—such as during an unrestrained motor vehicle accident.
Shortly after the announcement came that he would not throw at the NFL Scouting Combine, Mike Florio of Pro Football Talk clarified that Barkley's separation is of the type III variety. In other words, the hit tore both the AC ligament and CC ligaments in his right shoulder.
But that was three months ago. Why hasn't he healed yet?
Unfortunately, ligaments have relatively poor blood supplies when compared to tissues such as muscle bodies and skin. As a result, complete ligament tears can take an extremely long time to heal. Additionally, until a torn ligament fully heals, it is weaker and more prone to injury.
Yet that is not to say he isn't coming along.
As Florio mentions, Barkley has been progressing well under the care of Dr. James Andrews and "is believed to be at 90 percent." However, if Barkley were to go forward with the combine and push his shoulder beyond that 90 percent, he would risk re-injury, and ligaments are never quite the same after one tear, not to mention two.
Add in the fact the the injury is to Barkley's throwing shoulder, and it doesn't make medical or football sense for the former Trojan to play it anything other than completely safe.
With that in mind, the results of the medical evaluation of Barkley's shoulder at the combine become crucial. He will certainly undergo range of motion and strength testing to compare his current state to his previously normal one, and anything less than the expected 90 percent of full capacity will raise red flags.
In addition to physical exams, Barkley may also receive a shoulder MRI to gauge how his healing is progressing. Florio also reports that teams will receive information regarding the reasoning behind the medical decision to bar him from throwing.
Why is his shoulder function so important? Suboptimal shoulder range of motion would prevent Barkley from taking a full wind-up to throw and thus limit his range and accuracy. At the same time, less strength would shorten his maximum throwing distance as well as hamper his ability to muscle a ball out of a collapsing—or collapsed—pocket.
That said, once his torn ligaments have both entirely re-attached as well as cemented themselves back into place—which they will—Barkley will most likely look like his old self. However, no torn ligaments are ever quite as stable as they once were prior to injury, and any hint of an increased injury risk will be taken into account during draft weekend.
As a result, Barkley's draft stock continues to change at a seemingly daily rate. Bleacher Report's NFL Draft Lead Writer Matt Miller weighed in on that very subject:
Pre-injury, Matt Barkley's stock was on the decline due to his poor performance this season. As his offensive line regressed, so did his accuracy. Before hurting his shoulder, I had Barkley in the mid-first round based on his potential and NFL-readiness. Now, he's mid-second. The shoulder injury is concerning as he was already a limited arm passer, and now he's carrying the injury prone label. His stock is fluid.
It might all come down to USC's Pro Day. According to ESPN's Adam Schefter, Barkley is already cleared to throw at the March 27 event—another hint that he is extremely close to fully recovered.
Should Barkley demonstrate that his shoulder is fully rehabilitated at his Pro Day, his draft stock might take an upward turn. However, given the questions that already surrounded Barkley's arm strength prior to his injury, he'll certainly need to wow scouts to erase those doubts.
Yet that isn't the only challenge he faces.
As Miller mentions, Barkley's accuracy also came into question late last season. After completing 19 of 20 passes for six touchdowns against Colorado, Barkley's next four completion percentages were 63.3, 64.8, 60.6 and 52.6 percent (h/t ESPN). His nine interceptions over that four-week span also far surpassed the six he threw during the first seven games of the season.
To ensure a first-round selection, Barkley must show at his Pro Day that his late-season accuracy slide represents a fluke rather than a new norm—something he likely cannot do with an ailing shoulder.
For now, though, uncertainly reigns. Will he be able to reassert his once-elite draft status?
As has been the theme with Barkley for the past few months, only time will tell.
Dave Siebert is a medical Featured Columnist for Bleacher Report who will graduate from medical school in June. He plans to specialize in both Family Medicine and Primary Care (non-operative) Sports Medicine, and injury information discussed above is based on his own knowledge. Quotes were obtained firsthand unless otherwise noted.