22-year-old Berahino posted on Twitter on transfer deadline day that he would not play for the club again while Jeremy Peace remains as chairman.
Berahino missed out on a transfer to Tottenham after Peace blocked his potential departure, which infuriated the talented attacker, but Fletcher says things have since been smoothed over which allowed the player to feature for 35 minutes of Saturday's 0-0 draw with Southampton.
"People are emotional and you do silly things and when you're on Twitter it is there and you can voice your opinions," he said.
"With me, I moan to my mum, dad and my wife, whereas he's moaning to however many thousand followers he's got (76,000).
"I have had a word to him and we'll keep that private. The lads have given him a bit of stick. Sometimes that's the best way because it takes away the tension.
"Somebody comes in and has a little bit of a go at him and a little bit of banter and I'm sure he feels like one of the lads again."
Fletcher added: "He might not take on board everything you say but if he only takes on board a little bit and it makes him stop and think then I've done my job.
"If he starts working hard and producing for West Brom then he will have the fans back on his side.
"Hopefully that is it now - voice your opinion and now let's get on with it and help the team."