Diafra Sakho celebrates after scoring for West Ham
Sakho, 26, joined West Ham in the summer of 2014, having smashed 40 goals in his final two seasons with French side Metz - and he immediately made an impact in the Premier League.
The Senegal international hit ten goals in 23 Premier League games during the 2014/15 season, adding another two goals in other competitions to become an instant hit in East London.
However, the departure of manager Sam Allardyce and arrival of replacement Slaven Bilic led to fewer first-team opportunities last season, with Sakho starting just 18 Premier League games last term, hitting only five goals.
Now, with Hammers boss Bilic looking to strengthen his attack, Sakho could be pushed even further down the pecking order - prompting speculation over his long-term future at the Olympic Stadium.
Sky Sports now claim that Sakho has submitted a transfer request in a bid to leave West Ham this summer, and the suggestions of a move to Sunderland will only intensify as a result.
Sky Sports claim that Sunderland had an £11m bid for Sakho rejected a month ago, as his former boss Allardyce looks to reunite on Wearside.
The Black Cats need support for Jermain Defoe in the final third, and Sakho may well fancy the chance to work with Allardyce again whilst being handed regular first-team football.
Whilst Sunderland need to increase their bid, Sakho's desire to leave West Ham could put Allardyce in a strong position to land their man this summer.
How much do you think Sakho is worth?