Newly re-signed Sydney FC goalkeeping coach Zeljko Kalac has done his best to persuade Tony Popovic to coach the Sky Blues next season but says his great mate remains torn over his future.Crystal Palace assistant Popovic is a man in demand having met with officials from both the Sky Blues and the new western Sydney A-League franchise in recent days about head coaching offers.Popovic and Kalac were long-standing teammates for both Sydney United and the Socceroos and the pair met over lunch on Thursday as Popovic sought the advice of his close friend.Kalac, who re-signed as Sydney's goalkeeping coach for a further season on Friday, said he "tried my best" to talk up a return to the club for Popovic, a former Sky Blues player and assistant coach.But he predicted sleepless nights for Popovic over the weekend before an expected decision on Monday."He's got a lot on his plate at the moment and he probably just wanted to hear my opinion on certain things," Kalac said of the meeting."It'd be a difficult decision and you look at both sides of the fence - it'd obviously be great for him to come here and for us to be working together."... But on the other side, (western Sydney) is a new opportunity for him to start from scratch."He'd be torn, he'd be stewing over his decision ... I know him, he won't sleep."He's got a couple of great options and I'm sure he'll make the best decision for himself."He's a great coach and whoever gets him will be very lucky."Like Popovic, Kalac is a western Sydney product but said he always wanted to remain with the Sky Blues."Last year was my first year in coaching. I really enjoyed it and see the future in the club," he said."The future's looking bright for us, so hopefully stick around and start winning some things."Kalac took delight in overseeing the improvement of shotstopper Ivan Necevski, who displaced Liam Reddy as first choice keeper and was named Sydney's player of the season.Kalac is helping to short list potential candidates to replace Reddy following his sacking for being drunk on a team flight in March, but no signings will be made before Sydney have appointed a new coach.He also hoped to see the new western Sydney team prosper and urged Football Federation Australia to embrace the game's multi-cultural roots in the region in their establishment of the club."I hope they go back to old school a little bit," Kalac said.