But he says Friedel's contract - up at the end of the season - may be renewed.
"If he feels fine, why not?" he said. "We'll ask him in February. If he feels alright, we'll keep him. If he stays, he'll stay as the first-team keeper."
Friedel, a former United States international who is 40 in May, is close to becoming Villa's oldest ever player.
He will pass 1940s right-back Ernest Callaghan's record of 39 years and 257 days if he plays against Manchester United on 1 February at Old Trafford.
Can Friedel earn another contract?
Houllier, who met club owner Randy Lerner on Wednesday, said: "We are looking at several goalkeepers - and we've told Brad. We're looking for a keeper for the future.
"If Brad is fine in February, then we will keep him. We've told him that, if he feels OK.
"I've spoken to him and said 'obviously, you're 39, so I need to look to the future but I'm perfectly happy with you'."
Villa's assistant manager
Gary McAllister and goalkeeping coach Rafael Gonzalez were at Ibrox
to watch McGregor in late November as the club
lost 1-0 in the Champions League
to Manchester United.
Friedel has made
over 100 appearances
since
signing for Villa from Blackburn
in July 2008.
Houllier also confirmed on Wednesday that midfielder Steve Sidwell is close to completing a move to West Ham.
"Steve is having a medical," he said. "He's at the end of his contract (next summer) and it's not a secret that he lives in London. Otherwise I think Wolves would have been interested in signing him."
Source: BBC Sport
Source: BBC Sport