I mentioned this possibility a week or so ago and it wasn't well received. :-) In thinking about it a bit more I now realize why. With Marrero at 3B our problem isn't the defense from 3B, it's the offense there. What we'd essentially be doing is trading Marrero for Lin - which I see as more of a wash than an improvement. Both of them have good gloves but can't hit a lick.
You'll remember that I'm that 'solid up the middle' guy, the one who would have a GG'er at every position up the middle regardless of their offense (a bit of hyperbole there, but you get my point!) and give up some defense at the corners to get Silver Sluggers there. However, this team is so offensively challenged that we need all the offense we can get from every position. Consequently I don't see how trading Marrero for Lin solves our offensive problems and is, as I said, a wash on defense. We'd be doing nothing but rearranging the pieces on the board with no net gain at the team's weakness.