Martin Gray has branded criticism of Stephen Thompson by Curzon Ashton's manager John Flanagan disrespectful.
Flanagan brings his team to the North-East on Wednesday for a match between the division's top two sides and he has preceded the game by labelling Quakers' leading scorer as overweight and questioning his work ethic.
The comments came amid a debate about the nominees for the Evo-Stik player of the year on the NPL podcast.
Flanagan said: "He's a very good player, but he ain't much of a team player. He seems to go in one direction, doesn't track people, he waits to get on it, they carry him a little bit in respect of the defending.
"He's a right-footer playing on the left-hand side, he's chunky, looks a little bit overweight, but is deceptively quick and he drives inside and gets his shots away.
"I think he came out of the pro game at Port Vale. He's without a doubt a good footballer."
However, Flanagan does rank the 24-year-old among the division's better players, adding: "I don't see him pressing on the pitch. I see him walking a lot. But I did vote for him in my team of the year, so I do recognise that he's a top player."
After Saturday's 1-1 draw at Northwich Victoria, during which Thompson scored his 23rd goal in all competitions, Gray responded to Flanagan's comments.
"What he's said is very disrespectful," said Quakers' boss. "You keep your own counsel. I wouldn't speak badly of any other manager's team so I think it's very disrespectful to our club and to our player.
"You should speak about your own players. To conduct yourself in that manner is unprofessional and to talk about a player of Thompson's calibre too.
"The reason why he's being talked about is that he's scored over 20 goals this season, but it's very disappointing to hear what was said."