Chicago Bears vs. San Francisco 49ers Live Stream Free: Watch Online NFL Football (8:30PM ET)

(Photo: REUTERS)Chicago Bears quarterback Jay Cutler (6) lies on the field after being hit late on a play by the Houston Texans with his teammates over him during the first half of their NFL football game.

Chicago Bears vs. San Francisco 49ers is a highly anticipated matchup when two of the league's best teams will face-off, and in a twist of fate, both without their starting quarterbacks. So the big factor tonight will be how well will the teams' backup quarterbacks do. The game is scheduled to start at 8:30 p.m. ET and can be watched online through free live stream below.

When it comes to backup quarterbacks, Chicago Bears' Jason Campbell, playing in place of Jay Cutler, is expected to do better because he has more experience. Before joining the Bears, Campbell played for the Washington Redskins and the Oakland Raiders. In 2006, Campbell was named the Redskins starting quarterback, and also started for the Oakland Raiders but was soon demoted to back-up after a disappointing initial performance. But he was re-installed as a starter again later when his play improved.

49ers backup quarterback Colin Kaepernick will play his first career start tonight after Alex Smith failed medical clearance a week after sustaining a concussion. Second-year quarterback Kaepernick will face-off against eight-year veteran Campbell tonight at the 49ers' Candlestick Park.

"He's a veteran guy with a big, strong arm," said 49ers safety Donte Whitner, ESPN reported. "I never felt he got his fair shake in Washington, the guys he had around him, and Oakland, also. Once he got injured, they just shipped him out and brought another guy in.

"We understand that he can make plays, and we can't go into this game thinking we have it made and the backup quarterback is in there. That's when you get embarrassed."

The two teams' defense will put up a strong fight tonight, with the Bears' defense ranked second in the NFL in points allowed (14.8) and top when it comes to takeaways with 30. The Chicago Bears is at the top of the NFC North Team with 7-2, and the San Francisco 49ers ranks #1 in the NFC West Team with 6-2.

Chicago Bears vs. San Francisco 49ers starts at 8:30 p.m. ET and can be watched online through live steam by clicking here.