The 30-year-old returned to first team action for battling with illness caused by ulcerative colitis and was out of action since 2011, before returning in December 2013 after declaring himself completely fit.
Fletcher has less than six months left in his contract at Old Trafford and he could completed his switch to Upton Park before the end of the January transfer window.
Speaking about Darren Fletcher, van Gaal said at his press conference: "He is at West Ham now I believe, so we will have to wait and see."
— Manchester United (@ManUtd) January 30, 2015
“He is now at West Ham, I believe, so we have to wait and see,” Van Gaal told United’s official website.
“He is my third captain so he is an important guy in the dressing room. I like him as a person and as a human being so we shall miss him. But he hasn’t played so many times and that is always the main goal of a player. We have talked about that and he preferred to play.”
“Therefore, we have helped him to go away. It is a loss and, for the club that buys him, he is another player with a lot of quality – as a midfielder, but also as a captain and a very experienced player.”
“We also have another experienced player in the same role, so that is the problem here,” United manager concluded.