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As has been noted in the conversations recently, I have been one of main detractors against Sean Rodriguez. It isn't that I dislike Sean Rodriguez. I see him to be a valuable asset to any team, given his positional flexibility and his ability to hit in certain situations. However, like most players, Rodriguez has his flaws. Because of these flaws, I don't view Rodriguez as the answer to the shortstop position. Given his struggles in certain situations and the fact that the Rays are giving Elliot Johnson a roster spot, I believe it is in the Rays best interest to find a complimentary piece to the shortstop position, one that could help boost the overall production by facing high velocity pitchers.
It is widely know that Rodriguez features a drastic platoon split. The split can be seen in the graph below.

Now the major premise of arguments for Rodriguez playing full-time is that while he features a platoon split, his bat, overall, is competent enough to play everyday as a shortstop. I disagree with that statement. With a roster spot currently belonging to Elliot Johnson, the Rays have the ability to feature a platoon partner with Rodriguez. Scanning across the lists of MLB shortstops, there are very few who profile the role of a right handed pitching masher. In fact, very few fit the role of a competent bat against RHP.
Luckily for the Rays, I believe they don't have to find a SS who hits right handed pitching.
There is a cliche in baseball that players get to the major leagues by being able to hit the fastball. If you don't hit a fastball, you won't succeed in the major leagues. Apparently, Sean Rodriguez didn't get the memo (For the record, Sean Rodriguez does not need to hit much to qualify as a MLB shortstop).
It first occurred to me that Sean Rodriguez could be struggling with velocity when I read this article. The article focuses on swing mechanics and explains the problem with some swings regarding hand movement/positioning. Here is the quote in particular I am referring to:
The high level mechanics these elite use allow them to achieve bat speed before they commit to the swing and without moving their hands forward. In fact, their hands work back later and their load is the beginning of their swing. If we look at Gehrig, we can really see the movement of the barrel working back while his body turns forward. High level mechanics have the hands working up later because their swing is starting deeper, bat speed is occurring deeper, everything is moving… but there is still zero commitment.When kids load their hands back early (as part of the "get the foot down" process), they are getting their hands to position to swing from. The swing starts from that "up and back" position and the hands need to go forward to swing. This is a long swing, not a short swing! Moving the hands forward forward is needed to create bat speed. And they need to move the hands forward to both start the swing and create bat speed. The bat speed occurs out front. As kids face better pitching, their swing mechanics force them to decide to swing earlier because they need their hands to travel forward to get their swing up to speed.
As hitters, we want to be able to commit to our swing as late as possible. We want to hit the ball as deep as possible. We should be striving to teach mechanics that allow this to happen. Below are takes by Sean Rodriguez and Kevin Youkils to show two very different swing patterns. Rodriguez was a 3rd round draft pick and a .229 career hitter. Youkilis was an 8th round pick and is a .289 career hitter. Two very different hitters and I would argue Rodriguez is more naturally gifted athletically. Of the two, Youkilis is much closer to resembling what Gehrig does above. Rodriguez needs his hands to come forward to create bat speed. It forces a longer swing and an earlier swing commitment. Everything happens out front where Youkilis is creating bat speed that is deeper, behind him.
If you click the link, you will view a video comparison of Rodriguez's and Youkilis' swing.
This was an astute scouting observation by Bobby Tewksbary, but is it true in Rodriguez's case?
Rodriguez compiled 1030 PAs from 2008-2011, which, while not a huge sample size, is large enough, in my opinion, to search for a trend in his splits. To find out whether Rodriguez really has a velocity issue instead of a righty/lefty platoon split, I decided to look at Rodriguez's results against hard fastballs (92+ mph) and slower fastballs (91.9 mph and below). Below are the results:

Sean Rodriguez occasionally gets the reputation as a fastball masher, but apparently this isn't the case. It isn't surprising that there is a split here, but the stark contrast is surprising. Thinking logically, it would appear that velocity isn't really the issue, and that the real issue is still a lefty/righty split. After all, RHPs throw harder, so they will generally be grouped more often in the "High Velocity" group. However, the next graph offers an interesting twist to the dilemma.

It is very surprising, shocking rather, that Sean Rodriguez hits low velocity fastballs better that are from RHPs than LHPs.
Obviously, there are several variables that factor into this. First of all, only the wOBA versus fastballs is being calculated. It seems to be common knowledge that Rodriguez struggles against sliders from RHP, so that could help factor things out. The reason the wOBA wasn't calculated for offspeed pitches is because offspeed pitches are reliant upon a fastball. A solid changeup is harder to hit when the pitchers fastball in 95 mph than 88 mph. Despite all this, these findings do reveal some issues that Rodriguez has with velocity.
With these findings, it appears there is weight to the suggestion that Rodriguez struggles against velocity. The scouting finds this, and the stats do nothing to deny it. If Rodriguez struggles with velocity, then it is an unsolvable problem barring a mechanical adjustment. Because of this, Rodriguez's upside is relatively limited with the bat, and it appears he may be nothing more than a solid player who profiles well in some situations but who is a waste of the spot in the order in other situations.
So should the Rays call-up Brignac and platoon him in the right situations, such as against hard throwing pitchers? I don't think so. Brignac needs to solve his problems in AAA. Instead, I believe the Rays should target a shortstop who isn't fazed by velocity to platoon with Rodriguez.
With an open roster spot (no offense, Elliot Johnson), the Rays should look to find a player that complements Rodriguez, perhaps someone who isn't overwhelmed by high velocity. Considering that many starts can amp there velocity up on occasion, solidifying the SS position by acquiring a platoon piece for Rodriguez will help bolster the team.
For those who read the original piece, I corrected it. After re-reading it, I realized that the argument was a strawman, and I apologize for using such a weak argument. Enjoy!