Sunderland have rejected a bid for striker Connor Wickham from West Ham, BBC Newcastle understands.
West Ham are believed to have offered £4m for the 21-year-old Englishman, who helped Gus Poyet's side avoid Premier League relegation last season.
His five goals in three matches in April secured the Premier League Player of the Month Award.
West Ham are seeking cover for striker Andy Carroll, whose ankle injury is set to keep him out until November.
Wickham joined Sunderland in an £8.1m move from Ipswich Town in 2011.
He struggled to hold down a regular first-team place, starting just 28 Premier League games in his first two seasons.
He spent time on loan last season at Championship sides Leeds United and Sheffield Wednesday, before being recalled in March.