Details of the fee are unknown, although it is thought that the total fee will be around £4 million depending on appearences. The player was due to play in a reserve match tonight, ironically against Boro, but has been pulled out of it after the two clubs agreed a deal.
Johnsen, who can operate at left back or his favoured left midfield, has had a tough time at Leeds since signing for £7 million from Derby in 2000.