Current goalkeeper Clint Bolton has been given permission to leave the club and duly signed a two-year deal with new club Melbourne Heart as the Sky Blues are set to secure the services of current Wellington Phoenix gloveman Liam Reddy on a three-year deal once the finals series is complete.
And Kalac, who is a big wrap for Reddy, says it is the perfect time for Sydney to make a change of this magnitude.
''For 'Boutsa' [Bolton] it's the perfect time for a change,'' said Kalac.
''He's been there for five years, and obviously last year was a difficult one because he lost his spot. But this season he's come back fighting, he's been in great form, and that's when you want to be leaving, when you're on a high.
''With Liam, they're getting a much younger [six years] keeper whom I've got a big rap on. And when you look at the difference Johnny Filan [Sydney FC goalkeeping coach] has made for 'Boutsa' this season, Liam is lucky to be coming into that environment.''