Would Hatteberg be a fit (1B Scott Hatteberg of the Reds)? Sexson doesn't hit righties terribly well, and Hatteberg has a little bit of pop against them, so of course it's going to seem like a good fit. Any 1B that could hit lefties well would be a good fit. Greg Nortan is a switch hitting 1B who has a .667 AVG against lefties so far this season. Hatteberg is hitting .000 against lefties. He sure is smacking the ball against lefties.
Stats aside, the Mariners are going to have to give up something to get Hatteberg. Greg Nortan is already in the organization. Imeadiate advantage to Nortan. I'm not against Hatteberg, but why give up a mid-prospect for something that you already have?