"We have received two interesting offers, both of which are from English clubs," he told El Mundo Deportivo.
"What we always do is defend our interests. We won't sell any player if the bid is not the amount we have asked for.
Sporting director Paco Herrera revealed a deal for Riera had yet to be completed because the player was more interested in joining the club which had tabled the lowest bid, believed to be Liverpool.
"There is a team which is offering what we have asked and another one which isn't, but the player is interested in the one which is offering the least," he revealed.
"We will not lower our asking price."