Manager Mark Hughes made his move for the 30-year-old defender after Liverpool stepped up their interest in Fulham full back Paul Konchesky.
Mexican wave: Fulham are on the verge of signing defender Carlos Salcido
Although Wigan have also expressed fresh interest in Salcido, 30,Birmingham have dropped out of the chase leaving the deal to Fulhamclose to completion.
'We have made enquiries,' Hughes said after watching Fulham beat Port Vale 6-0 in the second round of the Carling Cup.
'He is a player I am interested in and we are hopeful it might be concluded.'
Reports last night stated that Fulham had agreed a fee with PSV.
Konchesky has been heavily linked with a move to Liverpool, where he would link up again with former Fulham manager Roy Hodgson.
But Hughes said: 'We are looking to have quality in all positions. Left-back is a position we are a little light in.
'It is not a foregone conclusion that Paul Konchesky goes because we are looking to bring someone else in.'
Birmingham boss McLeish increases bid for Wigan star N'Zogbia to £9m Hodgson eyes Konchesky reunion as Liverpool close in on Fulham defenderFULHAM FC