The 20-year-old played the last 15 minutes of Saturday's 0-0 draw at Newcastle United and has also earned rave reviews for his pre-season performances.
"Ravel is an emerging talent and we've very pleased with what he did in pre-season for us," Allardyce said.
"He is an exceptional talent who we hope we can nurture into the fray. Some people might say sticking a player on at that late stage might be risky but we've got to do it at some stage.
"We can see the talent and the only way to do it is to get him in the first team and get some minutes on the board.
"He'll play against Cheltenham and we'll see how he does and keep an eye on him.
"He's had a good season at Birmingham and he's brought that back with him in pre-season and it's great to see that talent is emerging."