The first question to ask is would Barajas be an upgrade versus the pre-existing options at Catcher.
As it stands, the Mets have options at Catcher just not very good ones.
Option 1: Henry Blanco
Probably the slowest running baseball player I have ever seen. His best-hitting performance which came last year still had him hitting slightly below league average. Generally limited to about 200 At-Bats a year...definitely a player I have never been high on.
Option 2: Chris Coste
Known more for not getting called up until he was 33 and writing a book about it. He hit fairly well in his time in Philly but his time in Houston was a pretty epic fail. Looking at the trusty forecaster, his home run totals should rebound to the 9-ish range but his drop in contract rate is a red light.
Option 3: Omir Santos
Looks to be the most likely option to start. Another player who didn't get to the bigs until fairly late (27) . Had a pretty mediocre season in his first extended shot with the Mets last year. Considering he's already pushing 30, it's safe to say any improvement offensively is going to be limited and if Shandler's forecaster proves right, the previous prediction sounds highly optimistic.
Option 4: Josh Thole
The youngest and most promising out of the bunch. Held his own in a September call-up but it's difficult to prove much over 57 plate appearances. Hits for a decent average but power and defense aren't amongst his strengths.
Looking at the other options, it looks like the Mets are going to be pretty weak behind the plate (unless Thole has a massive breakthrough this spring).....at first blush it looks like Barajas deserves at least a shot.....now time to actually look at Barajas:
Option 5: Rod Barajas
Historically, Barajas has been the polar opposite of Thole as he's historically hit for a terrible average but is a solid source of power. His average will rebound a bit as he had a low .234 BABIP
but expecting him to save the Mets is an expectation nobody has (as reflected by the modest 1-million dollar deal). Despite his pop, he has never had an OPS+ above 100 (something he shares with Henry Blanco).
Still, this is a case of the Mets being the Mets. While Barajas could help a decent amount of major league teams, the Mets aren't the best fit. The one strength of Barajas' hitting (home runs) is likely to be obscured by playing half his games in Citi Field where home runs seem to be suppressed. Pretty much, the Mets aren't better or worse off regardless of whether Blanco or Barajas is the back-up getting 200 plate appearances a year.