Leeds lost highly-rated youngsters Michael Woods and Tom Taiwo in February as they refused to sign schoolboy terms in favour of a move to Chelsea.
Former Leeds Academy coach Gary Worthington, against whom Leeds have issued legal proceedings against, had left Elland Road to take up a post at Chelsea shortly before the pair defected.
A Leeds statement read: "Leeds have instructed their lawyers, who have issued legal proceedings against Gary Worthington, in respect of breach of contract. The matter relates to the circumstances surrounding the signing of Michael Woods and Tom Taiwo by Chelsea FC."