Arsene Wenger does not want to be challenged by Alexis Sanchez and Arsenal have treated the forward poorly, according to Stewart Robson.
Manchester City are favourites to sign the 28-year-old, who revealed on Friday that he has already decided whether he will leave Arsenal, but will not confirm his intentions until after the Confederations Cup.
Sanchez only has one year left on his contract and ex-Arsenal midfielder Robson, who feels the club have handled the situation wrongly, believes Wenger does not like confrontations with players like the Chile international.
"It doesn't make sense, Sanchez has been outstanding for Arsenal," Robson told talkSPORT when asked why the Gunners have let has contract run down.
"But they did have a problem earlier in the season. Arsenal were putting it out that he didn't run as much as people thought he did, he was a problem defensively, that he had one or two arguments with team-mates.
"When things weren't going quite as well they were actually trying to tell the public that he wasn't quite the player that everyone expected him to be.
"He has been outstanding, their best player by quite some way over the last two years and it is wrong that they could just let him go like that.
"Arsene Wenger doesn't like confrontation and anybody that might challenge him, or might argue with one or two of his decisions, he doesn't like it and he doesn't want anyone like that at his club.
"Sanchez, as we have seen, when players aren't working quite as hard as he thinks they should do, or haven't passed him the ball, he will have a go at them.
"Sometimes that's a great attitude to have. You need three or four players that will get round the team, get after the players when things aren't going quite so well - as long as they are doing it themselves and Sanchez has certainly done it himself over the last two or three years."
Sanchez and Chile face Germany in the Confederations Cup final in Saint Petersburg on Sunday.