It was just the opening drive of the game, but it proved to be a costly series for the Green Bay Packers as quarterback Aaron Rodgers injured his non-throwing shoulder against the Chicago Bears on Monday Night Football and did not return to the game. Reports have indicated that the quarterback suffered a small fracture in his left shoulder.

Rodgers appeared to injure the shoulder when Shea McClellin sacked him with 12:38 remaining in the opening quarter. Rodgers had completed one pass to Jordy Nelson for 27 yards before his departure. After being evaluated by the team doctor, Rodgers exited the game and returned to the field in sweats in the third quarter as he was done for the night due to the injury.

ESPN reports that Rodgers was diagnosed with a small fracture in his shoulder and could miss up to three weeks, though more tests Tuesday will further determine his timeline.

Packers head coach Mike McCarthy didn't know of the severity of the injury following the game.

"He has a shoulder injury," McCarthy said via USA Today Sports. "They want to run more tests. They don't have an exact diagnosis. We'll have more information, probably tomorrow."

McCarthy added: "No timeline, no exact diagnosis. That's where we're at."

The reports early Tuesday morning came back that there now is a diagnosis and that Rodgers has a small fracture in his shoulder, which will likely sideline him for three weeks.

Seneca Wallace took over for the departed Rodgers in his first game under center in the regular season since January of 2012 with the Cleveland Browns. The veteran quarterback went 11-for-19 for 114 yards with no touchdowns, an interception and was sacked four times as Chicago eventually won the game 27-20 at Lambeau Field. The pick was made by Julius Peppers in the very first series for Wallace.

McCarthy knows that losing Rodgers for any length of time is a huge blow to the offense and noted that he didn't expect Wallace to play like Rodgers usually does.

"Aaron's a huge part of our offense," McCarthy said per USA Today Sports. "This is a thing that's been built over time with Aaron as the centerpiece. I don't think it's realistic to put anyone in there and expect him to perform [like Rodgers]."

Rodgers is 168-for-251 (66.9%) for 2,218 yards with 15 touchdowns and four interceptions on the year. Green Bay (5-3) has the same record as the Bears and the Detroit Lions after Week 9 in the NFC North.

If the timeline holds true, Rodgers will miss the next three games against the Philadelphia Eagles (4-5), New York Giants (2-6) and division rival Minnesota Vikings (1-7) before returning to face the Lions on Thanksgiving Day.