Hello. Here are two slash-lines:
.298/.396/.469 - 148 wRC+
.257/.423/.270 - 109 wRC+
These are two vastly different lines! The first represents an elite hitter. One who can command the strike zone to the tune of a very respectable walk rate and an isolated slugging of .170--if you sort batting leaders by ISO, this player would be nudged right in between Freddie Freeman and Matt Holliday. If you place this player by wRC+, he is the 10th-best qualified hitter in the league.
The second hitter is one with the best eye in the game. 2014's walk leader was Carlos Santana, with a 17.1 BB%. The player with the second slash line walks at a rate of 20.4%.
Here's the big unveiling: these two slash lines belong to Russell Martin. The first line is against right-handed pitching, and the second is against lefties. Russell Martin is a better all-around hitter against righties, yet has one of the best eyes for the zone in the game against lefties.
Add this to the fact that Martin is a highly regarded defensive catcher, and you get a player that any team would be happy to have. However, there is something a bit curious about the second slash line. Against lefties, Martin can barely hit for power. His ISO of 0.013 puts him 42 points below the worst qualified slugging hitter in all of baseball last year. It's not Derek Jeter (barely).
Here are all of Russell Martin's extra base hits against left handed pitching in 2014, in 98 plate appearances:
That's it. It was a double, and it was his only double against lefties in 2014. One double. No triples, no home runs.
How does this happen? How does a player with such an amazing eye for the zone manage to have such a terrible batted ball season from one side of the plate? From what is often a player's strong side, no less!
Here's the other thing--Martin's .257 batting vaerage against lefties was driven by a BABIP of .352. This will surely fall towards his career BABIP of .289, and the average and overall line will fall. But, if he can continue to dominate the zone from a discipline standpoint, then it won't matter all that much. If the Blue Jays position him in the lineup against lefties as a guy who can draw a walk one out of every five at-bats, but who doesn't really do much when he makes contact, then he can be an incredibly valuable piece.
But how does a player lose all power against opposite-handed pitchers and gain so much in terms of vision? Perhaps he was waiting back on pitches, trying to hit balls the other way against lefties?
Nope. All hits against lefties save one were to the pull side. Against righties it's actually very evenly spread out.
The answer may be hidden in PITCHf/x data.
For batters with at least 450 plate appearances against all pitching, Martin swings at the eighth-fewest balls in baseball, 21.1% of them, to be precise. He also only swings at 61% of strikes. He just doesn't swing all that much.
When you look at righty-lefty, the swing rates change.
One more thing as I rattle off platoon numbers on Russell Martin: when facing right-handed pitching he sees 4.14 pitches per plate appearance, and when facing lefties, the number changes to 4.46. Not all that much of a difference, but enough to see that clearly Martin focuses more on drawing a walk and working the plate against southpaws than trying to hit for power.
To summarize: Russell Martin swings far less frequently against left-handers, opting to try and get on base and taking a tremendous penalty in terms of hitting for power. Against right-handers, he is an extremely valuable all-around player.
Those slash lines again:
vs RHP: .298/.396/.469 - 148 wRC+
vs LHP: .257/.423/.270 - 109 wRC+
Against righties, Russell Martin is 2014 Yasiel Puig. Against lefties, Russell Martin gets on base more frequently than Carlos Santana and Jose Bautista. He can also do this: