"There has been interest from West Ham and they have officially approached us," Chelsea chief executive Peter Kenyon said on Friday.
"We're not looking to sell our players but if we get an offer we'll have to look at it on a serious basis."
Chelsea bought Wright-Phillips, 25, for £21m from Manchester City in July 2005.
But the England international has made only 12 league starts for Jose Mourinho's side since his arrival at Stamford Bridge, although he has come off the bench on 23 occasions.
The stepson of ex-England striker Ian Wright is yet to score a goal for the Premiership champions.
West Ham will have money to spend in the January transfer window following the takeover of the club by Icelanders Eggert Magnusson and Bjorgolfur Gudmundsson.
The Hammers made no official comment when contacted by BBC Sport on Friday.