"Mandeep Singh has sustained a finger injury, and has been ruled out of action for three weeks," BCCI Secretary Sanjay Patel said in a statement.
The tournament will be played in Indore from September 26 to September 29.
The 22-year-old Roy has played 17 first-class matches, scoring 704 runs at an average of 26.07. His list A tally of runs stands at 623 at an average of 28.31.