Burrow does look like Big Ben in his last year. The ball is just floating through the air.
The thing is about calves, you can't get any firm base when one is injured. That muscle, when it gets agitated, your leg is almost useless. You can get better push off with a sprained ankle....the calf though is just so much worse.
But the concerning part is the decision making and accuracy. That shouldn't be effected....maybe a slight decrease in accuracy. He's not even close to his targets on many throws that I've seen.