West Ham are waiting for Burnley to respond to their £27m bid for centre-back James Tarkowski.
Hammers boss David Moyes is keen to strengthen a defence that was vulnerable in Saturday’s 5-3 pre-season friendly defeat by Bournemouth.
Tarkowski, 27, joined Burnley in 2016 from Brentford, helping his team finish 10th in the Premier League last season.
He has two England caps but was not called up for the Nations League games against Iceland and Denmark.
West Ham are under pressure from fans after the sale of homegrown attacking midfielder Grady Diangana to West Brom, a decision that was criticised publicly by captain Mark Noble.
It is understood the sale was approved reluctantly by the Hammers. However, after owner David Sullivan injected money into the club to ensure bills were paid during the coronavirus lockdown, Moyes was told he would need to sell players before he could buy new ones.
Hoped-for deals involving Felipe Anderson and Manuel Lanzini failed to materialise, meaning West Brom’s offer for Diangana had to be accepted if Moyes was to be able to make signings he feels are needed to avoid a repeat of last season’s relegation battle.