Gera played the opening 45 minutes for the second team in their clash with Arsenal, scoring once and setting up another goal in a 3-1 win.
It was his first game of any sort since rejoining Albion in the summer for a second spell after being sidelined with various ankle problems.
Now Gera hopes he can be involved as a substitute against Villa.
The Hungary international said: "I've been in better shape and I was tired at the end. I felt I was fit sometime ago but then had another injury.
"Now I'm back and happy. I will keep training and hope to get back to my best soon.
"Fitness is the key now. I'm not ready for a full game but maybe 20-30 minutes.
"Saturday is the manager's decision but I will work hard and maybe 15-20 minutes would be good."
West Brom are optimistic defender Steven Reid will be available to face Villa after undergoing minor hand surgery following a challenge from Sunderland midfielder Lee Cattermole 11 days ago.
Cattermole claimed afterwards that Reid "rolls around like a girl." But Baggies head coach Roy Hodgson said: "I don't care one little bit what Lee Cattermole says.
"Players do themselves an enormous disservice making journalists jobs easier by giving them little headlines."