The Scottish international was one of former boss Graham Potter's six summer signings in 2018 and went on to feature in 31 of the Swans' games last season. But, under new head coach Steve Cooper, McKay has made just three appearances and all of these have been in the Carabao Cup. Even then, the winger has appeared for only a combined 120 minutes.
So, what's happened to the former Rangers flyer?
The 24-year-old hasn't been included in a match-day squad since the 2-1 defeat to Watford in the Carabao Cup back in September while his only appearance in an 18-man Championship squad was when he was an unused substitute for the opening day win against Hull City.
Even though the Scot performed decently under Potter - including a superb goal away at Bolton as well as a number of important assists - McKay is far from a loved footballer at the Liberty Stadium with Cooper at the helm.
Though regularly played out of position at Swansea with Bersant Celina favoured in the No.10 role, McKay has come in for stick from a swathe of the Swansea faithful.
The former Nottingham Forest winger should have been well on his way to staking a claim for a wing position with the departures of Daniel James, Luciano Narsingh and Jefferson Montero in the summer, but, he has instead become even more of a peripheral figure at the Liberty Stadium as the Swans hit promotion form in the first part of the 2019/20 campaign.
McKay has seen his route to the first team blocked by the return of Wayne Routledge and Nathan Dyer to the side, both of whom have been impressive in recent weeks whilst the previously outcast Andre Ayew and Celina have been found operating in wide roles also.
|Nathan Dyer and Wayne Routledge have performed well for Swansea.|
In fact, McKay has found himself even further down the pecking order with the likes of Aldo Kalulu and Kristoffer Peterson getting more game time as the season progresses. And, even when Celina has played out on the left, George Byers and Yan Dhanda have been preferred to McKay in the central role behind the lone striker.
With options appearing increasingly limited at the Liberty Stadium, the Scot cuts an ever-depressing figure. Though contracted until summer 2021, McKay is surely likely to leave if he doesn't get a chance, especially when considering he has even been relegated to the Under-23s of late.
It's sad to see the decline of a talented footballer, but sometimes players just don't fit at certain clubs. McKay's quandary seems exactly that.