Clark and El Ahmadi face Villa fitness tests
The pair sat out Monday's 6-1 thumping of Sunderland, a result that gave the club a big boost in their battle to avoid relegation.
"Ciaran hurt his foot in training the other day. Karim got a groin strain the other day too," Lambert told the club's website. "We will see how they are later in the week."
Villa are two places and five points above the relegation zone with 37 points from 35 games. Norwich are two places above them in 14th with one point more.