Eagles went on to make 143 appearances in three seasons for the Clarets, including a highly promising campaign in the Premier League.
The 25-year-old did well enough for Coyle to retain an interest.
And although the Scot decided not to raid his old club last summer when he was searching for reinforcements at Bolton, he went back to Turf Moor last month to snap Eagles up.
With Saturday's Premier League encounter with newly-promoted QPR at Loftus Road now given the green light, Eagles is set to make his second debut for Coyle, with his manager adamant the player has made rapid strides.
"He is a better player now," said Coyle.
"That was three years ago and he has picked up a lot along the way.
"There is no doubt he has got better year on year. He is desperate to do well and he will get the opportunity to play here."
Having played an integral role in the development of Jack Wilshere and Daniel Sturridge over the last two seasons, Coyle knows a failure to make a mark at one of England's leading clubs should not necessarily be viewed as a failure.
Although the stays of Wilshere and Sturridge were short-term compared to the three-year contract Eagles has signed, and the latter man is substantially older, Coyle believes it is merely a question of the player finding his level.
In Eagles' case, that might not be the Champions League. Coyle does feel he is worthy of a top flight place though.
"There is no shame in being unable to force yourself into Manchester United's starting XI," he said.
"Chris was part of the United first-team squad when I signed him. In fact, I agreed a deal for him before he went on a pre-season tour to South Africa. He ended up being top scorer.
"I don't know if Sir Alex thought about changing his mind but he had given me his word and the transfer went through."
At no stage was Coyle disappointed with his acquisition. And he sees no reason why it should be any different this time around.
"Chris was outstanding for me, both in the Championship and the Premier League," he said.
"Last year he scored 15 goals from a wide position.
"I know the quality he has. He wants to entertain, play the right way and be exciting. I believe he will be."
Eagles could be joined in the Bolton starting line-up by fellow new-boy Nigel Reo-Coker.
However, with Tuncay unavailable until he secures a work permit, there will be a familiar feel to the Trotters line-up as they look to secure a first top-flight triumph at the west London venue since 1978.
Source: Team Talk
Source: Team Talk