I like Marrero and think he could have been useful in Boston if they needed a utility infielder. But if I was a GM and needed one, I probably have a similar player already in my organization. And if I wanted Marrero, I know he is definitely going to get DFA'd at some point this off-season, if not this week when Nunez signs, then very likely when the Sox sign Martinez or Morrison or whoever. No rush to trade for him. At the very least, I would wait and see if he gets DFA'd to make room for Nunez.
The downside to trading for (or claiming) Marrero is then he has to be on the 25 man roster. However, if he clears waivers, he is free to sign a minor league free agent deal, giving his new team a little more roster freedom...