West Ham United want to be sure of Said Benrahma's long-term fitness before signing him permanently.
Benrahma joined the Hammers a week ago from Brentford on-loan for the season with a permanent option included.
Football Insider says the clause will be triggered if Benrahma passes a medical at the end of this campaign.
In connection with medical tests before the loan move, complications arose, which almost resulted in the deal breaking down.
Benrahma, an Algeria international, didn't make the bench for yesterday's 1-1 draw with Manchester City.