Houllier will run the rule over the 28-year-old Jamaica international with a view to a loan move in January.
'Aston Villa contacted us a few weeks ago with interest to see Omar up close,' Rapids managing director Jeff Plush said.
Rapids rise: Colorado star Cummings could be heading for the Premier League
'After discussing the opportunity with Omar, we felt it would be a good chance for him to get a leg up on pre-season training and at the same time get the experience of training with a Premier League club.
'Omar is a Colorado Rapids player. We explained to Aston Villa that we would be open to discussing a loan agreement for Omar until our season starts on March 19 if it benefited Omar and the Colorado Rapids.'
Cummings scored 14 goals last season as his side lifted the MLS Cup and Plush does not want to see his star striker leave for good.
He added: 'It would take Aston Villa or any club making a significant offer for us to even consider transferring Omar.'
Aston Villa to press ahead with move for Newcastle midfielder BartonWe're in a real mess: Villa winger Albrighton admits fears over poor formI'm glad to be back but I'm gutted we lost, says Villa's returning captain PetrovASTON VILLA FC
Source: Daily Mail
Source: Daily Mail