Why Justin Smith's Injury Could Put Huge Damper on 49ers' Playoff Ambitions

Zach Kruse@@zachkruse2Senior Analyst IDecember 18, 2012

ST. LOUIS, MO - DECEMBER 02:  Defensive end Justin Smith #94 of the San Francisco 49ers lines up prior to the play during the game against the St. Louis Rams at the Edward Jones Dome on December 2, 2012 in St. Louis, Missouri.  (Photo by David Welker/Getty Images)
David Welker/Getty Images

The San Francisco 49ers might have dodged an injury bullet that could have pierced a gaping hole through their playoff ambitions. 

According to head coach Jim Harbaugh, 49ers defensive end Justin Smith is expected to practice this week and play in Seattle this Sunday. Smith left the 49ers' 41-34 Week 14 win over the New England Patriots with an unspecified elbow/arm injury. 

Harbaugh had this to say today on KNBR radio, via Eric Branch of the San Francisco Chronicle

Everybody affectionately refers to Justin Smith around here as ‘The Cowboy.' I expect we’ll see The Cowboy. Knowing what I know of Justin Smith and the situation, I think The Cowboy will be around, saddled up … roping and riding. If it’s humanly possible, The Cowboy will be out there, roping and riding.

It's probably no coincidence that the Patriots' 28-point comeback Sunday night coincided with Smith's departure. 

Smith left with the 49ers up 31-10, then returned for one play with the score at 31-17. After he left for good in the third quarter, New England eventually tied the game at 31 before the 49ers landed the final punch. 

There's obviously no way to determine how the Patriots would have played offensively in the second half had Smith been on the field. And for argument's sake, the 49ers were poor on offense while tending to the seemingly insurmountable lead. 

But there's no question that losing Smith, who hasn't missed a start in 185 games, impacted the 49ers' ability to play defense. The Patriots scored 31 points in the second half. 

Smith underwent an MRI Monday, but those results were not released by Harbaugh. However, Smith's potential to practice and play this week suggests that the injury is not anything major. The dreaded torn biceps or triceps appears to be out of the question. 

The 49ers are lucky, because a major injury to Smith could have been a big blow to any Super Bowl chances this season. 

Smith, 33, has 66 tackles and 3.5 sacks this season. 

According to Pro Football Focus (subscription required), Smith has graded out as the fourth-best 3-4 defensive end in 2012. His biggest contribution has come against the run, where he's +18.4 in PFF's grading system. 

That said, Smith is still an integral part of the pass rush. 

The 49ers frequently utilize an inside-outside stunt with Smith and Aldon Smith on the right side of the defense. With Justin Smith pushing outside and driving the guard into the tackle, Aldon Smith can get a free release inside. The second-year outside linebacker has an NFL-high 19.5 sacks this season, many of which have come through this look.

For now, it appears as if Smith will be healthy enough to play Sunday, and then close to 100 percent for the postseason. That would especially be the case if San Francisco can secure a first-round bye. 

However, any set back or new information on the injury that knocks Smith out of the 49ers' lineup could be one of the most important injury issues of the NFC playoffs.

San Francisco could still make a Super Bowl run without their defensive leader, but the difficulty of such a task would certainly be magnified.