The 28-year-old joined the Hammers from Notting Forest for a reported fee of around £7 million, and has been at the club for nearly three years now.
Antonio is a versatile player who can play in multiple positions. However, his fitness remains a major headache and that is why the Hammers are prepared to consider offers of more than £15 million for him.
Last season he made just 21 appearances in an injury-hit campaign and West Gam are reportedly willing to offload him.
Pellegrini has begun his summer rebuild at the London Stadium and has made some exciting signings, but he should be looking to keep hold of Antonio, who earns around £70k-per-week at the club.
Even if they look to offload him, certainly they should demand a lot more than £15 million.