The 21-year-old full-back continues to spark transfer talk as Premier League clubs begin to piece together their recruitment plans ahead of the 2018-19 campaign.
With there no desire on the part of player or club to consider offers in the current window, the highly-rated youngster is being tipped to frustrate his growing list of suitors.
Former Celtic striker McDonald told BBC Radio Scotland: "I think he might possibly just stay on for even another year, maybe two more.
"If they're offering the amounts of money that can be offered down in England then it would be a huge temptation but we've seen in the past how much he loves the football club and he's still only young.
"If he holds out another year or two, I think opportunities do open up. Someone like Man United, that has been touted with the struggles that they have found at left-back.
"Certainly, if they were the ones tabling the bid, you would jump. I think you would have to jump to go to a Manchester United or the likes of them in the Champions League competitions. Everton, outside the top six clubs, you would argue are probably the next one."
He added: "It really depends on Kieran Tierney himself for me at this point.
"Celtic as a football club, I don't think they'll want to lose him but it certainly tests their resolve - if £25 million is slapped on to the table, that's a hard amount to say 'no' to and then I think pretty much it'll be in the player's hands.
"People are going to go mad when I say there's still a question mark on Kieran Tierney, especially at that level. The physicality and the pace of the game down there is completely night and day from what you get week in, week out here. I think he's more than willing, more than capable, to go and rise to that test.
"It's not so much him, it's what he's up against. It's the bigger physical specimen that he's going to come up against."
Another former Celtic star, Darren O’Dea, also expects Tierney to shun any interest shown this summer and follow a similar career path to Virgil van Dijk and Andy Robertson, with a stepping stone such as Southampton and Hull City taken before ending up at a leading side in England.
He said: "It depends where he wants to go. I might be wrong, not because of his ability, but I don't believe he'll move directly from Celtic to a top-four team in England.
"If he sees his career going to a Man United, whatever it may be, similar to Andy Robertson, I think he needs to make a step, I wouldn't say down - Everton's an unbelievable football club, a huge football club.
"Van Dijk's the perfect example. I think Van Dijk was as good as I've seen at centre-back."