Mitchell Trubisky’s debut started a quarterback controversy for the Bears

Mike Glennon is penciled in as the Bears’ starter this season — rookie Mitchell Trubisky even said so after the Bears’ 24-17 loss to the Broncos on Thursday, according to NFL Network’s Tom Pelissero. But 2017’s No. 2 pick made a strong case on Thursday for head coach John Fox to keep his options open.

Glennon struggled, and that’s the nicest thing we can say about it. He completed just two of eight passes for 20 yards. Trubisky, on the other hand, came in with 1:42 remaining in the first half and ran the team’s two-minute drill with ease.

He looked in command of the offense and hit veteran Victor Cruz on a 2-yard touchdown pass with 13 seconds on the clock:

In the second half, he looked comfortable and accurate throwing on the run, executing a 75-yard scoring drive on the Bears’ first possession:

He got the team in position for a fourth-quarter field goal, too:

Glennon wasn’t nearly so lucky. His second pass of the game was a pick-six. Poor line play didn’t help, but he never got into a rhythm, and it showed in his quarterback rating, which was zero:

Nobody expects Mark Sanchez to be anything more than a backup in Chicago this season. He didn’t do much to dispel that notion tonight, finishing 1-of-4 for just 4 total yards.

Trubisky was going up against Broncos players who are further down the depth chart, and it’s fair to point that out. But he still did enough to suggest that the Bears may want to slow down on the whole Glennon starting thing and see how Trubisky develops over the rest of the preseason.

Fox had to balance his reaction over Trubisky’s performance with the fact that it was just the first preseason game. He waved off concerns about Glennon’s performance and made it clear that the team’s “depth chart is not going to change after one game.”

Still, Fox is trying to ward off a quarterback controversy with his tempered reaction, but even though it was just the first preseason game, it’s probably too late for that.