Interim boss Ralf Rangnick has confirmed Henderson’s desire to depart after losing the battle for the No.1 spot to David De Gea.
Henderson had appeared to be first-choice for a period under Ole Gunnar Solskjaer, but has only played twice in the cups this season.
The futures of Martial and Van De Beek at Old Trafford also look bleak for similar reasons and former United striker Berbatov reckons United should offload this month.
“I’m not surprised to see that Dean Henderson has handed in a transfer request, I was expecting it,” Berbatov said, speaking to Betfair.
“Same for Donny van de Beek and Anthony Martial. These players aren’t playing and it’s clear they aren’t happy and as long as they love what they do, playing football, they should move.
“Henderson was bought to play in his view, David De Gea was going through a difficult period. Signings can galvanise a player, you’re not at your best then all of a sudden you have competition, so you gather yourself and start producing.
“That’s what happened with De Gea and it was bad news for Henderson. I fully understand why he wants to leave.”
Henderson’s transfer request has been rejected by Rangnick, who has said he would “rather have him stay until the end of the season”.
The 63-year-old was unbeaten in his first five games in charge but tasted defeat for the first time against Wolves on 3 January.
United bounced back in the FA Cup against Aston Villa but the performance was underwhelming yet again.
Berbatov has a theory for why Rangnick’s style of play and message isn’t quite translating thus far.
He added: “Having been a student of German football and having played there for five years I know that sometimes it takes a while to get used to new methods of training and practicing and knowing what the new coach wants tactically, and maybe the training can be a bit boring from time to time.
“These types of things can cause a bit of unhappiness and when you put that together with some not so convincing performances then you have this type of situation.
“However, look what Klopp and Tuchel have achieved at their clubs so far, maybe with a bit of time something similar could happen at Man United with Rangnick.”