Asked to confirm reports the England midfielder has had to undergo surgery on a hamstring injury some are speculating could keep him out until February, Bielsa would only say: "At the moment I have no precise news over his hamstring tendon or his shoulder (another problem Phillips has been suffering since last season)."
Phillips will definitely not play at Manchester City on Tuesday, as Bielsa selects from the same squad he took to Chelsea at the weekend.
He explained Struijk and Rodrigo are both suffering from pain rather than what he classed as injuries, and that both problems are highly unusual.
"The injury Pascal has is unusual," said Bielsa. "An explosive moment made two bones in his feet collide together and that doesn't generate an injury but has the effect of a knock on his bone and that generates pain.
"Until that pain disappears it's going to prevent him from playing. In my whole career I've never seen an injury like that.
"The same as Rodrigo's injury, an injury in his heel, which only disappears if the pain disappears, which I also haven't seen in many years. The specialists who treat it say there's very few cases like this."
Patrick Bamford, Liam Cooper and Robin Koch also missed the 3-2 defeat at Stamford Bridge.