This will place pressure on Pascal Struijk to step into his role, and he only lasted 20 minutes when he did so at Aston Villa earlier in the season before being hauled off unceremoniously.
A lot of Leeds' commitment to attack relies on Phillips being able to stunt counters at source - Pascal will have a big task on his hands to fill the shoes left by the England international.
Leeds, though, will be aided by the potential return of Diego Llorente in the heart of defence alongside club captain Liam Cooper who saw minutes last week in the FA Cup.
Another would be striker Patrick Bamford. He has taken the top flight by storm this season, scoring 10 goals in 17 games.
Scroll down and click through to see how Bielsa's men could line-up as the squatter takes on the Potter.
9. Rodrigo
The former Valencia man has just three goals this season but will be a threat to the Brighton rearguard
10. Jack Harrison
The 24-year-old Manchester City loanee is a lively customer and likes to attack from wide areas
11. Pat Bamford
Surprised many this season and has been in fine form for Leeds. Leads the line well and has an impressive 10 goals so far