It is understood that the Bulgarian is in 'good spirits' following his diagnosis, according to first-team coach Gordan Cowans.
"Stiliyan was up at the training ground last week, really looking and was feeling positive about himself, he's got a hard week this week with treatment but he is a fighter and will come through this," Cowans told Sky Sports News.
"He was so bubbly and he came in and took his hat off and has shaved his hair and looked very well. He is very positive and he is going to beat the illness."
Petrov was diagnosed with the illness on March 30.