Blues boss Villas-Boas was asked on Wednesday whether he would reverse his decision to banish Alex from his first-team squad should the club suffer an injury crisis. Alex and Nicolas Anelka were sidelined at Stamford Bridge after submitting transfer requests.
However, ahead of Monday's game against Fulham, Villas-Boas simply said: "No."
Any defensive crisis may last no more than a week, with Bolton boss Owen Coyle confirming the club were in talks with Chelsea over the transfer of Gary Cahill.
Villas-Boas said of Cahill, who Wanderers must sell to avoid losing for free in the summer: "He is extremely interesting, a player of course that terminates his contract.
"But we would be stupid if we shortened our targets just to one."
He added: "I think you know that we will be in the market for a centre-half. It's pretty obvious based on the fact that we've accepted Alex's transfer request.
"We'll have to let the market open and then find out what happens regarding Alex. We will have to respond quickly in the market, not because of the urgency but because we're willing to fill that position with one more central defender."
Chelsea have also been heavily linked with a loan move for Juventus winger Milos Krasic, who has been touted as a replacement for Shanghai-bound Anelka and cover for Didier Drogba and Salomon Kalou when they depart on African Nations Cup duty.
Source: PA
Source: PA