Manuel Pellegrini will reportedly have the final say on whether Javier Hernandez is allowed to leave the club in the January transfer window.
The Mexico international has netted nine goals in 36 Premier League appearances since joining the Hammers from Bayer Leverkusen last year.
According to The Express, United do not feel that the 30-year-old is technically good enough to lead the line, casting serious doubt over his future.
Hernandez is said to be seeking regular first-team football away from England, with Turkish giants Besiktas showing an interest in securing the striker's signature.
However, the report claims that Hernandez's move to Besiktas will only be sanctioned if Pellegrini agrees to the deal.
