Looking to add depth up front, the Knicks reached an agreement with former Wizards big man Kevin Seraphin on Tuesday.

Seraphin will a sign a one-year deal for the $2.8 million room exception, according to league sources.

The 6-foot-9 power forward/center had spent his entire five-year career with Washington, where he averaged 6.4 points and 3.7 rebounds in 16.4 minutes per game.

When the Knicks sign Seraphin, the No. 17 pick in the 2010 draft, they will have 13 players with fully guaranteed contracts. Langston Galloway has a partial guarantee, but he's expected to be on the team.

The Knicks have no more cap space left. Any other signings would have to be for the league minimum.

They used up their nearly $30 million available to them on Robin Lopez, Arron Afflalo, Derrick Williams and Kyle O'Quinn, and also re-signed Lance Thomas and Lou Amundson. The Knicks are expected to announce the signing of veteran guard Sasha Vujacic to a one-year deal in the near future.

With their remaining roster spot, the Knicks could look to add more wing depth. Last year's second-round pick Thanasis Antetokounmpo, who played for the Knicks' D-League team, could ink a partially guaranteed deal in the coming days. The Knicks also are expected to sign former Harvard swingman Wesley Saunders and ex-Virginia forward Darion Atkins as training camp invites.