Eric Chavez for platoon 1B? He hit pretty well in a limited role each of the last 2 years. That is more than the other candidates can say.
You wouldn't have to give up any players for him since he's a free agent (like you would in a trade for Mitch Moreland, Ike Davis, or whoever). His contract would likely be a 1-year deal (unlike Loney or the now-taken Morneau).
If he got hurt or didn't play well, then he's one and done. You could have Lambo down in AAA playing 1B for a couple of months while giving Chavez a trial run and splitting time with Gaby Sanchez.
My instinct is that he's one of those guys who likes playing for Arizona because he lives there or maybe it's close to home and that might especially strong pull for someone towards the end of their career. But, maybe he'll want one last shot at semi-regular playing time and do it on a team that made the playoffs last year.
It's not the best idea, but maybe one of the least worst ones compared to other options . . . like dealing prospects for a mediocre 1B or giving a multi-year deal for a lot of money to one who's upside is just so-so.