The race for unsettled Porto midfielder Hector Herrera is heating up.

The Mexico skipper has been linked with Real Madrid, where he would be reunited with former Porto coach Lopetegui. The pair are close and spent time together last month when Lopetegui was in Portugal on a short break.

However, Real won't get a clear run at Herrera should he become available in January.

A Bola says Arsenal and Tottenham are also keen. Both London giants had scouts posted to watch Herrera in Porto's Champions League win over Galatasaray this week. Also present were representatives of Crystal Palace.