After weeks of transfer no-goes, the former Bayern Munich star would be an outstanding option for Slaven Bilic's squad.
Mirco Antenucci left Leeds United this summer on a free transfer.
Watford have been linked with Sofiane Boufal.
The agreement strengthens the club's presence in South Korea, and emphasises the commercial value of Heung-Min Son.
HITC Sport understands Conor Grant heading for Valley
Conflicting reports are emerging about Aston Villa's move for Bristol City striker Jonathan Kodjia.
Sunderland are reportedly keen to make David Moyes their new manager.
Joe Allen is reportedly closing in on a move to Stoke City.
Leeds CEO signed Reece Wabara for Barnsley last summer.
The Northern Ireland captain is back in training with Southampton after the Euro 2016.
It is claimed that Leeds United hope to beat Wolverhampton Wanderers to Griffiths' signature, despite the Celtic striker appearing to have healed his rift with Bhoys boss Brendan Rodgers.
The former Spurs midfielder wants the salary if he is to join Everton this summer.
Leeds United boss wants transfer backing if he is to sign a long term deal.
Newcastle United are the latest club to be linked with a move for Manchester City's Kelechi Iheanacho.
Liverpool have replaced Southampton as early favourites to sign Manchester City's Gael Clichy.
Liverpool have been linked to Arsenal ace Alex Oxlade-Chamberlain.
Liverpool are expected to be highly active in the summer transfer window.
Newcastle United are among the favourites to sign the Watford man this summer.
The FC Twente midfielder is said to have caught the eye of Leeds United and could be on the move this summer.
Rangers boss Pedro Caixinha is said to desperately want the striker at Ibrox, and could have the upper hand over Derby County.