Boss Gus Poyet has snapped up the Argentine striker from Spanish La Liga side Almeria for an undisclosed fee, but the Seagulls are awaiting international clearance.
Assuming it comes through Ulloa is likely to start his Albion career on the bench.
Fellow forward Craig Mackail-Smith should be fit after missing last Saturday's 2-1 win over Derby as a precaution due to a tight hamstring.
But defender Bruno looks set to miss out for the fourth match running due to an Achilles problem, with fellow Spaniard Inigo Calderon set to deputise once again after he overcame a knee injury to face the Rams.
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