An impressive preseason from No. 2 overall pick Mitchell Trubisky forced the Chicago Bears to promote him from third on the depth chart.

“He’s one play away,” offensive coordinator Dowell Loggains said Wednesday in confirming Trubisky had leapfrogged Mark Sanchez to become Mike Glennon’s top backup at the position.

Trubisky completed 67 percent of his passes in the preseason and showed more mobility and overall athletic ability than some draft evaluators credited him for; even head coach John Fox, not prone to hyperbole, said the team was impressed.

“He earned that spot,” Fox said. “Everyone was impressed how fast he picked things up.”

Glennon signed a three-year deal in free agency that includes $16.5 million guaranteed for 2017. He is a season-opening starter for the first time in his career, but the structure of the contract — the Bears can back out of the deal with minimal financial impact — and Trubisky’s presence are significant factors spelling a short stint for Glennon as the No. 1 guy for the Bears.

Glennon was named a team captain this week and was praised by Fox for showing leadership throughout the preseason.

Loggains said “overall knowledge” was the one area in which Glennon holds the big advantage over Trubisky. But the rookie has shown veteran-level poise on a daily basis with the performance to back it up.

“No matter how much you throw at him, he’s the same every day,” Loggains said.

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