have told Liverpool it will cost them £90m if they want to sign Gelson Martins this summer.
The winger was in impressive form last season and he has carried that into the new campaign by bagging two goals in as many games.
The 22-year-old has been on the Reds' radar and they had been alerted to his £54m release-clause.
However, according to A Bola, Liverpool are in for a shock as Sporting are set to ramp up Martins' price.
The Portuguese newspaper claims Sporting can increase the winger's release clause to £90m if they make a one-off payment of £1.