Pep Guardiola admits Joe Hart could make him live to regret the decision to allow him to leave Manchester City.
Former City goalkeeper Hart returns to Manchester with new club Burnley on Saturday.
Hart won five major trophies at City, including two Premier League titles, before falling out of favour after the arrival of Guardiola as manager in 2016.
The 31-year-old spent two seasons out on loan at Torino and West Ham before joining the Clarets in a £3.5million permanent deal last summer.
Guardiola said: “I know how tough it was for the fans, for the people. He was an incredible keeper and had incredible results here in the club. That’s why it was not easy for me, to take a decision.
“I’m not always taking decisions that are right. I have made in my career good decisions and very bad decisions, but you have to take it in the right moment and at the right time. Sometimes I took it and afterwards I’ve regretted. That’s what it is – that happens.”
Hart joined City from hometown club Shrewsbury in 2006 and established himself as first choice in the 2010-11 campaign, after being loaned to Birmingham the previous year.
His sudden displacement from the side in 2016, first by Claudio Bravo and then Ederson, meant that the club were unable to pay proper tribute to the player for his services at the time.
The champions have addressed that this week with the naming of the goalkeeper training pitch at the City Football Academy after him along with the unveiling of a mosaic bearing his image.
Hart was invited to a special opening ceremony on Thursday and a further presentation will be made on the pitch this weekend.
Guardiola said: “I think there is no doubt how important he was and is. Tomorrow you will see how people appreciate what he has done for this club.”
Despite Hart’s pedigree, Guardiola felt Hart was unsuited to his style of play, which places emphasis on goalkeepers playing out with their feet.
Guardiola was impressed by Hart’s professionalism during the period in which he was out of the side.
Speaking at his pre-match press conference, Guardiola said: “Normally the player thinks of himself, himself, himself – it’s not easy – but he put himself a little bit in my position and said he understood perfectly. That’s why I appreciate a lot his behaviour.”
Hart, who made 348 City appearances, said the pitch renaming was a “huge honour”.
He added: “Manchester City has been a huge part of my life and my career, and I’m immensely proud of what I and my team-mates achieved in that period.
“There have been some incredible goalkeeping legends throughout Manchester City’s history, and I feel privileged that the club has chosen to recognise me amongst that number.”
Guardiola meanwhile said, “Yes, the club are working on it” when asked if new contract negotiations had begun with winger Leroy Sane. The 22-year-old German has two-and-a-half years remaining on his present deal.
Guardiola added: “(It is) not (just) for the recent performances. We value the quality of the player, the human being, how settled he is.”