Speculation has surrounded the future of the Belgium international all season, but Jagielka insists there should be no doubts about his team-mate's commitment to the Premier League club.
"He had a painful ankle problem before the City game and he could have milked it and missed the game before disappearing off on international week but he was desperate to play," said Jagielka.
"He strapped himself up and put in a great performance. You cannot question his commitment.
"Felli has taken all the beatings for us throughout the season and he will feel sometimes like the world is against him. Sometimes it has been.
"You can forget he is not that old. He hasn't grown up in the Premier League for all his career and hasn't been at this level as long as others."