Oxford United manager Chris Wilder has claimed Celtic attempted to acquire his latest signing Michael Duberry in January.
Wilder agreed a two-year-deal with the 35-year-old defender to join the Us after a recommendation from Celtic coach Garry Parker.
But the League Two club's boss admits Duberry, who arrives at the Kassam Stadium from Scottish outfit St Johnstone, was researched thoroughly before being signed, despite interest from the Hoops earlier this year.
Wilder said: "We don't just sign players on a whim. We've done extensive homework on Michael. He's mobile and he's ambitious.
"I've got to say a thank you to Garry Parker, who gave him a really good reference. Celtic showed an interest in him at Christmas and they were looking to bring him into the club, but Michael wanted to play regularly.
"He got his career back on track by playing football and going up to Scotland. He's been excellent up there.
"People talk about the standard of the Scottish game, but you play Celtic and Rangers four times and there's some good clubs like Hearts and Hibs and good players up there."
Duberry, who made the move from McDiarmid Park to be nearer his family in England, will now join a squad hoping to improve on their 12th-placed finish last season.
And the former Chelsea centre-back is relishing the prospect of a season with a club he believes are moving forward.
Duberry added: "I'm here because I want to play football. I like the way the club's going and I want to be part of something successful."