Based on blog posts, comment sections and Twitter exchanges regarding free agent hitter Ryan Garko, here is how I would generalize a conversation between a pro-Garko and an anti-Garko Mets fan:
Pro: Ryan Garko! Platoon with Murphy! .887 OPS vs. lefties!
Anti: He's one dimensional. Or even 1/2 dimensional. Can't hit acceptably vs. righties for a first baseman, as you seem to know.
Pro: .887 OPS vs. lefties.
Anti: His first base defense isn't good.
Anti: He's a terrible athlete and baserunner. Embarrassing anywhere except first base. Hitting well vs. lefties is his only discernible skill.
Pro: What's OPS?
The snark might be excessive in this little dialogue but it is an appropriate response given the amount of love Garko has been receiving from Met fans. The negatives to a Garko signing outweigh the lone positive.
For whatever reason, the Mets don't appear to view Daniel Murphy as anything but a first baseman. Murph's value would be enhanced if he could accrue some experience in the outfield or (God forbid) at second base. However, the Mets' brainstorm seems to think a guy with a minor league OPS of .796 should only spend time at first base. Whatever, that's a topic for another day. A Garko signing would give the Mets two players projected to play just one non-premium position. The 29 year-old Garko has barely played any outfield in his career and in that limited sample was poor. His Speed Scores are among the worst in the game and all scouting reports portray him as unathletic, so putting him in the outfield is out of the question. He's not a good fielder at first base, and is projected at something like -3 per 150 games, a glorified DH.
This lack of versatility is the main reason he doesn't fit. "Versatility" might sound like a meaningless buzz word overhead at a corporate pep rally ("synergy", "client centricity", "targeted workforce reduction"), but it is important with this Mets team. Three of the five bench spots are filled, by Alex Cora, Angel Pagan/GMJ and yet-to-be-named backup catcher. Signing Garko would provide the slightest of upgrades at first base while ignoring the need for a competent reserve outfielder and someone to backup David Wright at third base. At this point, the Mets would be better off letting Murphy play everyday (gasp) and turning their attention to improving second base and the outfield. What they don't need is a lead-footed DH who specializes in crushing the type of pitcher who the Mets can expect to face roughly 25%-30% of the time next season.