ESPN.com is reporting that team doctors have diagnosed the serious injury to the knee of Steelers’ quarterback Byron Leftwich as a sprain of the medial collateral ligament, or the MCL. The injury occurred in last night’s game, and it was initially feared that Leftwich might be lost for most, if not all, of the season. Given the suspension to starting quarterback Ben Roethlisberger, this was feared to be a devastating blow just prior to the start of the season.

According to the report, team doctors ordered an MRI to assist with diagnosis. The injury supposedly only involves the medial collateral ligament and does not involve the anterior cruciate ligament. An ACL tear would almost certainly have meant Leftwich would have missed the entire season and needed surgical treatment. Instead, Leftwich suffered a second-degree MCL sprain. Likely, this involves a high-grade stretching of the ligament or even a partial tear, but it does not sound like he suffered a complete tear of the ligament. It is likely that team doctors will place Leftwich in a brace that allows his knee to bend but prevents any stress to the ligament itself. Typically such an injury can take anywhere from 1 to 6 weeks to heal, but it rarely require surgical treatment.

Read more about medial collateral ligament (MCL) injuries.