DESPITE Bryce Gibbs seeking a trade to Adelaide at the end of last season, Carlton CEO Steven Trigg is confident the midfielder will fulfil his contract at the Blues.

Gibbs is signed up until the end of 2019 after he put pen to paper on a five-year deal in 2014.

However, family reasons played a role in Gibbs requesting a move back to his home state.

His son Charlie turned two in June.

Trigg spoke of his confidence on Melbourne radio station SEN on Saturday that Gibbs would stay.

"I don't see any reason to say anything different. He's contracted for two more years at the end of this year (and) he's happy," Trigg said.

"I think part of that's reflected, as you can see, in the way that he's playing.

"We don't detect the personal issues that led to that issue arising last summer.

"I can sit here quite confidently and say that he's a Carlton player next year."

Gibbs, 28, averaged 28 disposals per game in his 13 matches this campaign going into the clash with Adelaide on Saturday afternoon at the MCG.

Meanwhile, key forward Levi Casboult will be an unrestricted free agent at the end of the season.

"We're really confident of him staying and like a number of players around the competition in that position, we'll knuckle down to it towards the end of the season," Trigg said.

Casboult, 27, ranked ninth in the competition for contested marks per game going into round 15 and had booted 20.10.

The unusual nature of coach Brendon Bolton's contract has some concerned he could be picked off by another club. Instead of being signed up for a fixed term, Bolton's situation is similar to other staff members and he is on a rolling contract.

"I know there's a bit of mystique about this but I'll try to be really clear. Yes, it's a different form of arrangement, but there are protections in there in terms of periods of notice that protect both him and the club," Trigg said.

"It just doesn't have a sunset on it."