The contract is for one year, Kerala Cricket Association (KCA) said.
The 21-year-old Sandeep hails from Thrissur and had made his debut in Ranji Trophy in this season where he has claimed 24 wickets from five matches.
Sandeep, who was was among the highest wicket-takers for Kerala in the last couple of years, was selected to BCCI fast bowlers academy this year.
He also attended Indian university camp.