You could always just offer him the rat, he may take it no problem. If he doesn't seem interested in the rat, thaw out a mouse and rub it all over the rat "scenting" it. This is what got my female to take her first f/t rat. After scenting it once, I never had to again, she switched over pretty easily.
1.0 '12 Irian Jaya Carpet Python
0.1 '09 Normal BP
1.0 '07 Normal BP
1.0 '08 Pinstripe BP
0.0.1 Nelson's Milk Snake
____________________
0.2 Horses (Egyptian Arabian & Tennessee Walker)
2.2 Dogs
1.1 Cats