Mets did well by acquiring Johnson
Johnson is the ideal caddy for right fielder Shawn Green, who can no longer hit left-handed pitching or catch fly balls that aren't hit directly at him. Johnson's bat may be stretched as an everyday corner player, although he's a good athlete and could develop into a borderline producer in right. He's a good defensive right fielder with average power and good plate discipline, and I think he'll add a little more power if he learns to extend his arms slightly and pull certain pitches. Even so, he slots right into the Mets' lineup every day that an opposing lefty starts and can be Green's defensive replacement, perhaps increasing his role after Green leaves.
Adkins is just another mediocre right-handed reliever without an out-pitch. He has an average fastball, 88-92 mph, which has well below average movement; a below-average curveball; no out-pitch; and no real weapon against left-handed hitters, against whom he works well away from any contact. He's useful while he's cheap, but isn't someone likely to return real value once he's eligible for arbitration.