Arriving for the first day of trade week at Etihad Stadium on Monday morning, McKay said Carlton would be lodging the paperwork in their bid for Thomas - believed to be a four-year deal worth $2.8 million - later in the day.
"We haven't got him but we'll certainly be putting the paperwork in today," McKay said.
"I can't talk on Collingwood's behalf but we'll make obviously a reasonable offer to Dale and see what happens.
"(It) depends on Collingwood I suppose whether they want to give us an indication today or over the next three days."
Although Thomas was reportedly told not to attend Collingwood's Copeland Trophy function last Friday night, the 26-year-old insisted there were no ill will between himself and Magpies coach Nathan Buckley.
"He took it really well," Thomas told Fox Sports from Melbourne airport.
"I obviously called him up ... Bucks has got no hard feelings.
"It's an exciting time not only in my career but in my life, so I think the papers get lodged today and obviously Collingwood has the chance to match that in the next three days.
"But at this stage it looks like I'll be heading to Carlton and I'm very excited about it.
"I've obviously had a tough couple of years and when this opportunity arose with the free agency and the like I just thought it was right to move on and getting to Carlton, I'm very excited, getting back with (Carlton and ex-Collingwood coach) Mick (Malthouse).
"They're a team on the improve and hopefully I can play some good footy there."
McKay, meanwhile, wouldn't comment on rumours ruckman Shaun Hampson may be headed to Richmond.
"We've got a number of people who are up for grabs," McKay said.
"But certainly we have a number of people that clubs have shown interest on, it just depends."
In an interesting twist, the Carlton contingent arrived at Etihad Stadium at the same time as St Kilda's, with Blues coach Mick Malthouse deep in conversation with his embattled St Kilda counterpart Scott Watters.
Saints football manager Chris Pelchen wouldn't speak to the media on the way in, but Western Bulldogs list manager Jason McCartney was more forthcoming when asked about the Dogs' quest to sign Essendon forward Stewart Crameri.
"I think there's a fair bit of work to do," McCartney said.
"Obviously Stewy's said he wants to come and play for the Bulldogs, that's part A.
"But you've got to try and get a deal done with Essendon so the Bombers are within their rights, he's an Essendon player.
"So like I said, we've just got to work through it.
"I don't know how long it will take to be honest but we'll open up discussions officially today."
Newly-signed West Coast coach Adam Simpson also declared that Victorian moves for midfielder Luke Shuey were misguided, despite suggestions Melbourne may even offer up their number two draft selection for him.
"Nah he's (Shuey) not going anywhere," declared Simpson. "He's one of us."
West Coast have also failed in their bid to select Luke McDonald as the Eagles' first-round draft selection bid for McDonald was matched by North Melbourne. North will now take McDonald, the son of Donald, as a father-son selection.
Brisbane have also committed themselves to selecting Lions Academy player Johnathan Freeman with their round four draft selection.