By Chris Emma–

CHICAGO (CBS) — After a strong showing during the preseason, Bears rookie Mitchell Trubisky has been elevated to the second-string quarterback spot.

READ MORE: Chicago Weather: Colder And Blustery Sunday Night

Coach John Fox made that decision official Wednesday at Halas Hall, the first changing of the guard at quarterback since Trubisky was drafted second overall in April. Mike Glennon will remain the team’s starter while Mark Sanchez is now the third-team quarterback.

Trubisky went 36-of-53 for 364 yards, three touchdowns and zero interceptions in the preseason. The Bears’ determination for this move in the depth chart was mostly based by how Trubisky has shown the poise necessary to play in an NFL game months after being drafted.

“He has surpassed everybody’s feeling,” Fox said. “All the coaches, personally for myself, I think his teammates. We were asked to evaluate him all the way through. I think everybody was pretty impressed with how fast he picked things up.”

READ MORE: Shedd Aquarium Asks Restaurants To Help Keep Plastic Out Of Great Lakes

Trubisky will work as the backup quarterback in practice and will share reps with the scout team alongside Sanchez. The Bears this past weekend opted to keep Sanchez on the active roster and carry three quarterbacks, with offensive coordinator Dowell Loggains citing his experience as being beneficial for the quarterback room.

Loggains has seen first hand the readiness Trubisky shows in leading the offense.

“He deserves a ton of credit, because he worked his tail off,” Loggains said of Trubisky. “With virtual reality, watching his iPad, studying the playbook. He earned the spot. He put himself in position to be successful.

“This kid never gets rattled. No matter how much you throw at him, no matter how hard you coach him, he’s the same guy every day.”

MORE NEWS: Outbound Kennedy Expressway Ramp To Montrose Avenue Reopens Monday

Chris Emma covers the Bears, Chicago’s sports scene and more for Follow him on Twitter @CEmma670 and like his Facebook page.