My reasons are two-fold:
a) Even though I said after round 3 that Brett Finch would make Blues halfback, I think it's a bit early for him. I predict he'll have a shocker tomorrow night and that will shatter his confidence and this will show on Friday.
b) Newcastle are my worst team as far as tipping goes. I think I've got 5 Knights games correct all year. Therefore, if I tip the Knights again, I'm a good chance of jinxing them again and thus enabling the Roosters to get up.