The 20-year-old Austrian scored his first goal in the top flight at the weekend with a late winner against Fulham to give Villa a much-needed three points.
Agbonlahor told the club's official website: "He's been banging in goals for the reserves and has scored a couple of hat-tricks for them recently.
"He got a brief cameo against Blackburn and he would probably have preferred a bit longer but it is good for him to be involved. It is encouraging for the team that there are a crop of young lads who are hungry and desperate to get in the team."
"I am disappointed for him but these things happen in football," added Agbonlahor. "He has got a strong mentality and will be back as soon as possible."