I think one of the "attractive" reasons for signing Abreu is to not pay Vaughn $6 million. So, if the Sox are not going to spend money, especially at first base, there are probably several options out there:
Carlos Santana
Joey Gallo
Anthony Rizzo
Josh Bell
Rowdy Tellez
Just to name a few. Most of these guys, including Abreu, would cost less than Vaughn. Do they provide better options offensively and/or defensively? Do they provide better peripherals than Vaughn (leadership, clubhouse presence, etc.)?