I expect Santino Marella to be a consistent jobber to whomever he faces on Raw for the next period of time. Then he'll end up on Heat where he will continue in the same role, with a few occasional appearances on Raw to give Sandman some practice with his aim with the cane. Finally he'll either be released or sent back to OVW for an extended period of time so that he can actually learn how to wrestle in the WWE.
Terrible gimmick. Should never have been given the IC belt as a randomly chosen "fan." Average wrestling skills at best. Hopefully upon his return it will be a fresh start on Smackdown with a new gimmick, this Italian face thing is not cutting it at all.
His only other possible saving thing may be a heel turn immediately. Enter Maria. Have Maria be all over him, then he attacks her and achieves instant heel status (see Torrie Wilson and Carlito). As a sudden heel, his gimmick gradually changes, his wrestling style does too, and he may be able to survive.
Otherwise he's destined for an extended stay in OVW, or even worse, he'll end up in the WWE reject organization known as TNA.