The Red Sox would like catcher Jarrod Saltalamacchia back in Boston. Salty would similarly like to be back with the Red Sox. Where the two sides diverge is on just how long Salty should be in a Red Sox uniform, according to ESPN Boston's Gordon Edes: Saltalamacchia is looking for "at least three to four years" on his next contract, with the Red Sox only interested in retaining him on "short years".
This shouldn't be a surprise: Boston's interest in a long-term Brian McCann deal stems from the belief he could shift to designated hitter or first base if necessary in the later years of his contract. Salty's bat is not McCann's, and is a fit mostly due to his being a catcher, so such a deal wouldn't work for him -- yes, Saltalamacchia was above-average offensively with room to spare in 2013, but expecting a repeat performance is asking for disappointment, given his strikeout rates and lofty batting average on balls in play. The concern about blocking the plate for too long is legitimate, though, as the Red Sox have the duo of Christian Vazquez and Blake Swihart sitting in the upper minors: Swihart is a top-100 prospect who is well-liked by plenty of scouts who see him as a high-quality starter, and Vazquez has his fans as well, who think he could handle starting in the majors someday, thanks to his batting eye and superb defense. The two could very well be ready for the majors by 2015 or 2016, lessening the need for a long-term catcher contract, and increasing the desire for more of a bridge backstop to help get these two settled in on their own schedule.
This is why the Red Sox are interested in Carlos Ruiz, who is older, sure, but will also likely sign for just two years, with a third possibly as an option. The market is out there for Saltalamacchia to ink a three- or four-year deal, too: MLB Trade Rumors actually predicted Salty to the White Sox for four years at $36 million total, and that seems both sensible and reasonable. Both sides will likely end up getting what they want, but it just won't be with each other.