Rumours have been rife that Colosimo has become disgruntled since the captaincy was stripped off him and handed to Brazilian import Fred late last week.

Cross-town rivals Melbourne Victory are reportedly very interested in the 33-year-old Socceroo.

But while Bolton has described the possibility of Colosimo departing the Heart as a 'non-issue' for now, he is preparing for the worst.

"I've been in this game long enough to know that where there's smoke generally there's fire," Bolton said.

Bolton said Colosimo would be hard to replace if he walked out on the Heart.

"There's not a lot of good players in general, let alone good defenders floating around that haven't been signed," Bolton said.

Bolton revealed the playing group was initially shocked when Fred replaced Colosimo as Heart captain but now thinks it was a great move by coach John van 't Schip.

"I just thought Matt Thompson would be captain but then thinking about it, I think Fred is an inspired decision by the coach," Bolton said.

"Now playing with him as a team-mate it (my respect for him) has just gone to another level."

"His attitude, his professionalism on the park is first class. It's just an example for the younger boys out there to really follow."

Meanwhile, Bolton has declared himself a certain starter in the Heart's season opener against Newcastle at Ausgrid Stadium on Saturday after fully recovering from shoulder surgery in February.

"The shoulder's fine, it's golden, it's 100 percent," said Bolton.