The Finn, who has played more than 500 games in 14 years with the Trotters, was surprisingly rested for last weekend's 1-0 defeat by Blackburn as he is pressed by Hungarian youngster Adam Bogdan and Oman international Ali Al Habsi, currently on loan at Wigan.
"Ali was allowed to go on loan to Wigan because I felt he'd been understudy for too long and he had to play," Coyle said. "There's no problem regarding all the positions in our team. It's a fair fight. As a manager, I think the best one will play in that position."
He added: "I knew the qualities he (Al Habsi) has as a goalkeeper, I also knew young Adam Bogdan is an outstanding keeper who's getting better. So for us it was always a win, win, win situation.
"When the season finishes at Wigan, and Al Habsi's been one of their best players this year, he'll return to Bolton Wanderers, and that's very clear."
Coyle, meanwhile, insisted last week's decision was taken purely to give Jaaskelainen a rest and Bogdan a rare chance to play in the Barclays Premier League.
"Jussi was great," the Trotters boss said of his keeper's reaction. "Jussi's been outstanding all season, as he has from day one at the football club.
"I spoke to him and I said, given the amount of games we've had in a short period of time, that we were going to give young Adam a game at Blackburn, and he was comfortable with it.
"He'll play in goal against Sunderland on Saturday. As a manager, that's the decision you make. It was made for the right reasons."
Source: PA
Source: PA