Initial reports suggested Phillips would be ruled out for up to six weeks, but Bielsa gave a glimmer of hope that the 24-year-old could return sooner than expected.
Bielsa said: “I don’t have the definitive amount of time that Phillips is going to be out for. I understand that the information is incorrect. It could be more, or it could be less.”
Phillips has started all of Leeds’ Premier League games and earned his first England call-up under Gareth Southgate, and Bielsa bemoaned the timing of his injury.
“An injury is always uncomfortable and always comes at an inopportune time,” added Bielsa. “And it comes in a moment that is very special for Kalvin.”
Bielsa confirmed that Pascal Struijk, who replaced Liam Cooper on Monday after Cooper was injured in the warm-up, will come into midfield in place of Phillips against Aston Villa on Friday night.
Cooper remains an injury doubt for the Villa game while fellow centre-back Diego Llorente, who returned from international duty with a groin strain, is still definitely sidelined.
Bielsa said: “I can’t confirm whether Cooper is going to be available or not, as we’re two days away from the game and we’re still not sure if he will be.”
