Tena met with Ferguson last Monday in Manchester to discuss the availability of Javier Hernandez for the London Olympics.
"We spoke to Ferguson, who was friendly and we discussed several future possibilities. He gave us a tour of the facilities offered by Manchester United and asked if we wanted to train there.
"We even talked about two players who they are following."
Tena refused to identify the players, though its understood Tigers striker Alan Pulido and America defender Diego Reyes are on United's agenda.