Scott McDonald insists he suffered no falling out with Tony Mowbray prior to his departure from Celtic.
The Australia international was one of a host of former Hoops to make their way to Middlesbrough during the January transfer window, with Boro boss Gordon Strachan raiding his former employers for five fresh faces.
The North East outfit are reported to have splashed out £3.2million on McDonald, a man who boasted an impressive scoring record during his time in Scotland and was regularly handed the opportunity to strut his stuff in the UEFA Champions League.
His decision to join Championship outfit Middlesbrough has come as a surprise to some, with speculation regarding his motives already doing the rounds.
McDonald, though, insists his decision was based purely on the desire to find regular first-team football in World Cup year, and had nothing to do with his relationship with Mowbray.
He said: "I wasn't too happy with not playing as regularly as I would have liked. There was no fall out, as was suggested, between me and the manager.
"There was nothing like that going on. Relationships were very good. They wanted me to stay at the football club, but I felt I needed to get more game time.
"I had worked under this manager [Strachan] beforehand and I believe I played my best football under him, so it was another chance to team up with him and Garry Pendrey and try to progress even more as a player and keep getting better and better.
"With the World Cup at stake at the end of the season, that was a massive factor also."
Meanwhile, Boro have confirmed that their efforts to extend Isaiah Osbourne's loan spell at the Riverside Stadium have been dashed by the midfielder's parent club Aston Villa.
"We did look at extending Isaiah's loan to the end of the season but Martin O'Neill wanted him back at Villa because they have a few injuries too," said Strachan.