Report: Arthur is wanted by Spurs
The attacking left-back has another year to run on his deal but the club have an option for another 12 months.
Masuaku joined West Ham from Olympiakos on a four-year contract for a £6.2 million fee in August 2016 and has made 75 appearances in all competitions.
Earlier this season it appeared he was destined for the exit door in the summer after some woeful defensive displays which cost West Ham dearly but his form has greatly improved since then and he finished the season as the number one left back.
Manuel Pellegrini is thought to hunting for a new left-back this summer to bolster the squad and provide competition but it more likely that Aaron Cresswell would be sold if his valuation is met this summer transfer window.
A Claret and Poll last week suggests that supporters want him to stay with 971 votes in his favour of staying and 685 against.