Middlesbrough have accepted an undisclosed offer from West Ham for midfielder Gary O'Neil.
The Teessiders confirmed that they have given the Barclays Premier League club permission to talk to the 27-year-old.
A statement said: "Boro have accepted an undisclosed bid from Premier League club West Ham for midfielder Gary O'Neil. The Hammers have been given permission to discuss personal terms with the former Portsmouth man."
O'Neil joined Boro in a Â£5million switch from Portsmouth in August 2007 under former boss Gareth Southgate.
He initially struggled to settle in the north-east and was linked with a return to the south coast on several occasions, but he eventually found his feet and was appointed captain as he established himself.
However, Boro's relegation from the Barclays Premier League and failure to win promotion at the first attempt have put ever greater pressure on the club's finances, and with little sign of a push for the top flight materialising this season, purse strings are having to be tightened.
David Wheater, who like O'Neil was on Premier League wages at the Riverside Stadium, joined Bolton last week, and his former team-mate seems certain to follow him out of the exit door as the club hierarchy attempt to keep a tight rein on spending.
Current boss Tony Mowbray will also hope the sales will generate a transfer kitty for him to do his own rebuilding work with no cash left for new signings following predecessor Gordon Strachan's shopping mission.
O'Neil could be set to team up with Demba Ba at Upton Park after the Hoffenheim striker claimed he was joining the Londoners until the end of the season. The 25-year-old said the two clubs had agreed a six-month loan deal.
"I'm really happy that the clubs have reached an agreement," Ba said on his personal website, www.demba-ba.eu. "I was eager to join the club and meet my new team-mates. I'd like to thank Hoffenheim for allowing me to join that team. I thank my family and all my fans for their support."