Ander Herrera said Manchester United's offer of a new contract came too late following his arrival at Paris Saint-Germain.
Herrera has joined PSG on a free transfer and signed a five-year deal with the club, having made up his mind to join them before United made him an offer of their own.
"I don't like looking at the past, but there were differences regarding the project and my importance within it. I was very happy, I have a lot to thank the club for, the fans and also [manager Ole Gunnar] Solskjaer.
"He did a lot for me to stay, but things didn't happen. They arrived late and, by then, I'd already made the decision to play in Paris."
The Spaniard reflected on a "fantastic" time during his five years at Old Trafford, which included winning the Sir Matt Busby Player of the Year award in 2016-17.
He added that he would not have left United for a domestic rival: "Why PSG? Because to leave United, the biggest team in England, you need something like PSG, which is the biggest in France. I could not play in another English club."
According to the Press Association (h/t the Guardian), with PSG having saved money on a transfer fee, Herrera is thought to be earning a premium wage at the Parc des Prince of almost £350,000 per week.
James Robson of the Evening Standard reported United's offer was in excess of £200,000 per week.
As BBC Sport's Simon Stone noted, Herrera wouldn't have got the same length of contract at Old Trafford, either:
The midfielder was a useful asset to the Red Devils over the years thanks to his tenacious work in the centre of the park.
However, as Bleacher Report's Rob Blanchette observed, it would not have made much financial sense to tie him down on a bumper new deal:
Herrera will be 30 in August, so he'll be on the verge of his 35th birthday by the time his PSG contract comes to an end.
While some players can continue to be effective contributors well into their 30s, others can suffer a sharp decline in a short space of time when age catches up with them, so a lengthy deal at this stage in his career is something of a gamble from PSG.
Naturally, what United must now do is bring in a replacement for Herrera. The former Athletic Bilbao midfielder was a good player for the Red Devils, but not so much that they shouldn't be able to find a younger and more affordable player who can perform a similar role.