McGuire said the deal was a mere formality and praised the 24-year-old for rebuffing lucrative offers from rival clubs.
"That's 100 per cent correct [he is close to signing] - not signed yet, but close enough," McGuire said.
"Daisy has been good enough all the way through that he had no intentions of leaving the club - he hasn't tried to extort us or anything like that.
"But there are a few elements to these deals that have to be signed off on by the AFL with the salary cap and all that, so that's basically where we are at the moment."
The deal will keep Thomas at the club until at least 2013, when he will become a restricted free agent after eight years service.
After this period, players can move teams if their current club is unwilling to match a rival club's offer.
"It's just a matter of putting it to bed, which is fantastic news because he is just a wonderful player for our club, a wonderful bloke."
"For supporters who have loved 'Daisy' in the past, they should absolutely love him [now] - he could have obviously got more money, we could have blown our salary cap to kingdom come,' McGuire said
