Having reached the age of 33 without winning a cap, international football seemed to have passed Davies by until he was called up by Capello last month and made his England debut as a substitute against Montenegro.
It meant that Wanderers, who were fighting relegation last term when Coyle was appointed manager in January, had two players in the senior national set-up with Davies joining his club colleague Gary Cahill in Capello's squad.
It speaks volumes for the way things have changed over the course of 2010 for Bolton, who are now sixth in the Premier League thanks to an impressive 4-2 win over Spurs at the weekend.
As Capello watched from the stands at the Reebok Stadium, Davies boosted his chances of an international recall with an eye-catching two-goal display and Coyle believes the Wanderers skipper should now be a shoo-in for the England squad to face France on November 17.
"I'd be disappointed for Kevin if he is not and, given the fact that Mr Capello was there on Saturday, I'd be very surprised if he is not in that squad," Coyle said.
"From when we came in in January, when we were favourites for relegation and really up against it, to where we are now, obviously we have improved.
"If in January someone had said you will have two players in the England squad and you'll be safe, we would have grabbed that with both hands."
Now Coyle hopes to see Davies establish himself as an England regular and is confident the forward has plenty to offer at that level.
"I think Mr Capello knows it, because he has already brought him in for the last game and he will know that Kevin did ever so well in those last 20 minutes (against Montenegro)," Coyle said.
"I would have loved for him to be given longer because I thought he would have been a real thorn in their side, and I think if he is given that opportunity again we will all see his quality.
"He is so patriotic and desperate to represent his country, and to have that sort of player wanting to wear the shirt with immense pride, it can add another 10% to him."