COLLINGWOOD coach Nathan Buckley says "it's a bit sad" that Pies premiership player Heritier Lumumba harbours such bitter memories of his AFL career.

In an explosive, soon-to-be released documentary about Lumumba's life, the 2010 All Australian defender accuses Buckley of lacking "sensitivity and emotional intelligence".

As revealed by Fairfax Media on Saturday, Lumumba also accused the Pies of – among other things – racism, claiming he was called "Chimp" around the club.

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The 30-year-old, who has lived overseas since March, retired from the AFL last year after suffering a series of concussions while playing for Melbourne.

When Lumumba's criticisms were raised in Buckley's post-match press conference after the defeat to Geelong on Saturday, the Pies coach said his main concern was Lumumba's welfare.

"I read (Lumumba's comments) this morning and it's a bit sad, in many ways, that ‘H’ feels that way about his experiences in the game," Buckley said.

"He's been a great contributor to our footy club for a decade, for his 199 games (for Collingwood), and I shared those times with him as a player and then as a coach.

"I suppose I'd echo the sentiments of the club, just hoping that he's doing well and that he can still see the positives of his experience as an AFL footballer as well."

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Asked whether he lacked emotional intelligence, as Lumumba had suggested, Buckley dryly remarked: "He wouldn't be the first bloke to think that.

"Personally, I've always looked out for, and been aware of, H's issues, or his concerns or his challenges, and tried to support him as best as I possibly can in my role as teammate, captain and then as line coach and senior coach," he said.

"There's a bit more that goes on than just the one anecdote at one moment."

As for the "Chimp" nickname, Buckley insisted he "didn't hear it".

"This has the capacity to get out bigger than it needs to be, but I'm conscious of H and where he's at at the moment and, as I said, hope he's doing well.”