Wigan manager Roberto Martinez says Ashley Williams is "not a nasty footballer" after the Swansea defender came in for criticism after striking Robin van Persie with a ball hit from close range.
The Manchester United forward was lying on the ground following a foul when Williams kicked the ball into the back of his head during Sunday match at the Liberty Stadium.
United manager Alex Ferguson said Van Persie was "lucky to be alive" after the incident in the 74th minute of the 1-1 draw.
Martinez, who managed Swansea before joining the Latics in 2009, admitted he could understand Ferguson's reaction but does not believe Williams, a player he signed and knows well, acted out of malicious intent.
"You see the incident and it is a very, very dangerous situation," Martinez said.
"If you see one of your players with a bang on the back of the head it is really dangerous and it can have bad consequences. You can understand that.
"I signed Ashley Williams for Swansea and I know his character inside out. I can guarantee you without even looking at the incident that he is not a nasty footballer.
"He is a winner and fully committed, a leader and a captain, and I don't for one second doubt that he did not do that on purpose.
"It is an action of the game. He can show frustration - it is an emotional game and it is very unfortunate that it hits Van Persie in a part of the body where he could have been hurt heavily, and you don't want to see that.
"But from my point of view, I know Ashley Williams really well - when you sign a player you find out about a player and I can guarantee you he is not the type of footballer who would do that on purpose."
Ferguson, who has called for Williams to be banned by the Football Association, looks set to escape punishment himself for comments he made about referee Michael Oliver.
The Scot boss was angry that Oliver allowed Swansea's equaliser to stand after Chico fouled Van Persie during the build-up.
Ferguson said: "It really it should have been a foul for us when the defender fouled Van Persie, but the referee has had one of those games.
"I know he is a young referee but, dear me, what a performance that was."
QPR boss Harry Redknapp, speaking ahead of his side's St Stephen's Day clash with West Bromwich Albion, said of the Williams incident: "I don't see how he was going to be killed.
"He kicked the ball at him. I have seen worse things on a football pitch."