Jess Hornby/Getty Images
Leeds United will have to include a guaranteed permanent purchase option in any deal to sign young defensive midfielder Dario Essegu from Sporting Lisbon, according to journalist Alan Nixon.
The Whites have shown interest in signing the teenage midfielder from the Portuguese club and even attempted to strike a deal last summer.
However, the Portuguese champions sent the teenager to La Liga club Las Palmas, where he has gone on to become a regular.