Young whipper snappers like Andy Robertson and Ryan Gauld have leapfrogged him in the queue of talent being shipped out of Tayside, earning multi-million pound moves to Hull and Sporting Lisbon respectively this summer, but the 23-year-old Scotland winger enters the final year of his contract with a fair measure of uncertainty hanging over his future.
While negotiations are under way about an extension to his deal, nothing has been finalised and you get the impression the player isn't exactly agitating for a swift resolution. While United, even rich with the profits of their summer transfer business, will be wary of letting him walk out of the door for nothing, the only reported interest has come from Bulgarian outfit Ludogorets and Mackay-Steven may prefer to take his chances in the Bosman market next summer.
Whatever happens, having already had one crack at the big time with a move to Liverpool as a teenager, the player knows the next six to 12 months could define the parameters of his career.
"It's definitely a big year for me," Mackay-Steven said ahead of today's Premiership opener against Aberdeen. "I've seen boys get big moves and I'd like that myself. But I know I need to get my head down and play the way I can in order to get there.
"There are rumours all the time, you're always hearing stuff, but I don't really listen to any of it. I'm really happy for the boys that have moved on. They had great seasons last year and they deserve everything that they've got.
"There has been talk about a new contract but I just want to concentrate on my football right now. I want to start the season off well and see where it takes me. My agent is speaking to the club but I'm just focused on the football."
It is 30 years since Dundee United and Aberdeen were said to comprise Scotland's new firm, and while United also have the small matter of their city rivals to contend with during this campaign, a top flight bereft of other derbies is likely to witness a further flowering of this North East grudge match. The Pittodrie outfit won three and drew one of their meetings last time round, a record United will be keen to improve upon in the quest to be best of the rest.
This afternoon Aberdeen have the added benefit of the competitive edge provided by six keenly-fought Europa League ties against FC Daugava Riga, Groningen and Real Sociedad.
"They might be a bit fitter and sharper than us having played six competitive games," said the product of Thurso, on Scotland's remote north coast. "But we've played games as well, albeit friendlies, and we've been working hard. Come Sunday we'll be ready for anything they throw at us. The fans look forward to this game and the players do too. There's always a great atmosphere, whether it's at Tannadice or Pittodrie.
"On paper you could say it looks like us versus them for second. Aberdeen are probably slight favourites given what they achieved last season but we want to be up there. But there are other teams who have strengthened, even Dundee who have come up and looked good in pre-season. A lot of other clubs will have a good season, but we're focused on ourselves and we want that second place.
"Andy Robertson had a fantastic year and he left so you might look at that as weakening us, but we'll see as the season goes on who comes in and steps up. Looking at pre-season and the way training has gone, I'm excited for the season ahead and what we can achieve, so hopefully we can do the business on the park."
In the firing line today is a man synonymous with United. David Goodwillie, who spent two separate spells at Tannadice, pitched up at Pittodrie this season and Mackay-Steven feels it is only a matter of time before he reminds Scottish football what he has to offer.
"We all know how good he is and I think Aberdeen is a great move for him," said Mackay-Steven. "He'll be a massive danger on Sunday if he plays and if he gets a run of games under his belt he'll be back to being the striker we all know he is. He showed it in glimpses here last season and if he gets his confidence up he'll be flying."
Had things gone differently, today's encounter could have been a battle of cup-winning sides, but for both Mackay-Steven and United, the season didn't end as they had hoped. The winger fell victim to an ankle injury in the final at Celtic Park, powerless to prevent Jackie McNamara's side succumbing to St Johnstone. Such setbacks will fuel United's season.
"Personally and for the team I feel the season didn't end as well as it could have," Mackay-Steven said. "I missed a few games through illness then in the cup final we didn't cover ourselves in glory. St Johnstone grabbed it and we didn't and that was a bit of a downer, but we're refreshed now and we want to go one better."
If that is to happen, input from the likes of Mackay-Steven and Stuart Armstrong, two men who earned full Scotland honours last term, will be crucial. Mackay-Steven, who became a YouTube sensation on the strength of some of his feints and tricks, has been expanding his repertoire behind closed doors. "I've been trying a few in training so hopefully they come out on match days," he said.