Phillips withdrew from the England squad for their recent World Cup qualifiers against Andorra and Hungary after suffering a calf problem in his club side’s Premier League win over Watford.
The 25-year-old also missed the 1-0 defeat at Southampton which left Leeds 17th in the table with just one win from their first eight games of the season.
“Kalvin is healthy but has not competed for three weeks and if he played on Saturday it would be far too quick,” Bielsa said ahead of the Whites’ game against Wolves at Elland Road.
“After three weeks out is necessary for him to have some more football training and in this stage he has done training sessions for recovery and physical preparation.
“I think that to think of him for Saturday would be to bring him back too soon before he is back at his best.”
Luke Ayling, Patrick Bamford, Junior Firpo and Robin Koch also remain sidelined, but Raphinha is available to face Wolves after “acclimatising” on his return to England following his starring role in Brazil’s 4-1 win over Uruguay.
Bielsa admits the manner of the defeat at Southampton means this week has been one of the most challenging of his time at Leeds, who finished ninth on their return to the Premier League last season.
“There have been five or six, but this has been one of the most difficult,” he added. “The complexity of the week prior to a game is dependent on how far away we were in the last game.
“The Southampton game, the distance between what we were playing for and what we achieved was very far, and that (the defeat) was deserved. For me it is a very sad week.
“In a parallel way, I know the errors that we made, I know those errors could have been avoided if I managed it more efficiently so I have a lot of energy, strength and willingness to avoid what happened in that game happening again.”