Skipper Luke Murphy has still only managed a little light jogging since picking up a groin injury in mid-March, while top-scorer Mathias Pogba is a major doubt after limping out of Monday's 1-0 win over Preston with a thigh problem.
Davis is likely to take both to the capital on Sunday regardless of their current fitness levels if they have even the slightest chance of featuring.
However, the Alex chief admitted he will require big performances from the rest of his squad if the star duo miss out.
"Murph has done a bit of running and the sounds we are getting from him are quite positive," he told the Crewe Chronicle.
"We'll take him down there anyway because he is vital to what we do - our most consistent player.
"We're hoping Pogs had more of a cramp than a pull but time will tell.
"You hope if big players are out others come in and do well. Wembley is a day for heroes. This is an opportunity too good to miss."