Cabaral, 22, is on the radar of English clubs after some excellent performances for Sporting.
His surge in form led to Sporting raising his price-tag beyond the €15m they were willing to negotiate at before.
Sporting received a ‘concrete proposal’ of €10m for Cabral from Fulham recently, which they deemed too low.
The English club tried to anticipate competition for winger Cabral by bidding first, but their move failed.
The Cape Verde international has scored five goals since the Portuguese league restarted.