Based on some great work from Dan of Pistons Powered (with an assist from Kevin Pelton of ESPN), the Raptors have just a 5.1% chance of keeping their pick. You can go there and play around with different teams. This number is based on projections for remaining games and then applying lottery odds to the odds of finishing in each spot.
A reminder that with the win last night, the Raptors are 30-48, the 10th worst record in the NBA. Based on who is around them and the number of games left, that seems like their most likely landing spot, which would provide for a 4.0% chance of getting a top-three pick.