While coaches and players continually backed the 25-year-old power forward to choose the club who had taught him everything over its rivals, Thompson said he wasn't so sure.
The writing was on the wall, he said, from the moment Tippett refused to sign a contract with Adelaide.
"There was a lot of speculation of what his career path was going to take, I had convinced myself that he wasn't going to be here, purely [on] the fact that he hadn't signed," Thompson revealed.
"If he wanted to be here, with the ups and downs he's had this year with concussions and what not, if he wanted to stay he would have signed a long time ago.
"The fact that he didn't, I pretty much got my head around the fact that he was leaving, that's proven to be the case and as I keep touching on, good luck to him."
Thompson said he was supremely confident the club would overcome Tippett's departure and succeed next season.
The 29-year-old, who snared his second consecutive club champion award from Patrick Dangerfield on Friday night, made the stunning claim that Adelaide's current list was the best in the club's history.
With the likes of Josh Jenkins and Shaun McKernan waiting in the wings, Thompson said the Crows had ample replacements for Tippett, even without selective recruiting.
"We've got the list that, with or without him (Tippett) that we're going to create a very successful environment," he said.
"I think it's the best list that the club's ever had together … our depth is great and it's exciting times going forward.
"We've got a number of blokes that can come in and fill his role straight away," Thompson said.
"Jenkins has proven this year that he's more than capable of playing at the level and as a 29 year-old that's been in the system for 12 of years now, I'm really excited by what the future holds."
Crows chairman Rob Chapman also refused to lay the boot into the outgoing Tippett.
But he left the star, who was absent on Friday night, with cautionary advice on how he should leave the club that gave him his first shot at AFL football.
"The way you leave the club is so important, dignity, respect, character in tact; this should be everyone's aim and I'd like to think we have a rich history in achieving that - Neil Craig as a recent example springs to mind," Chapman said.
"Kurt is a good person … Kurt had everything and every opportunity to become the best person and footballer he could whilst being at our club.
"At no stage was money ever an issue … the reasons why he's going is Kurt's decision alone and how he chooses to communicate that is entirely up to Kurt.
"[We] sincerely wish Kurt well for the future."
Coach Brenton Sanderson was slightly less sympathetic, claiming he was ready to "start taking some boys back" from rival sides.
In recent seasons, Adelaide has lost Nathan Bock, Phil Davis, Jack Gunston and Kurt Tippett to interstate sides.
Harry Thring is a repoter for AFL Media. Follow him on Twitter: @AFL_Harry.
