Diego Costa has been on trial with Wolves after injuries to forwards Sasa Kalajdzic and Raul Jimenez.
The Premier League are assessing Costa's fitness and suitability during the trial period.
Costa, 33, has been without a club since leaving Brazilian side Atletico Mineiro in January.
Kalajdzic, 25, suffered a knee ligament injury during his debut in Saturday's win over Southampton.
He had only joined Wolves on Wednesday from German club Stuttgart.
Scans showed an anterior cruciate ligament injury and he will see a knee specialist on Monday.
Costa has previous Premier League experience with Chelsea, playing a key role in their 2015 and 2017 title triumphs.