May 5, 2013; Arlington, TX, USA; Texas Rangers relief pitcher Joe Nathan (36) pauses between pitches against the Boston Red Sox in the ninth inning at the Rangers Ballpark in Arlington. The Rangers won 4-3. Mandatory Credit: Jim Cowsert-USA TODAY Sports

What Is Wrong With Joe Nathan?

On the surface, Joe Nathan‘s 2013 season thus far does not seem to be anything out of the ordinary—20.1 IP, 2.21 ERA and 8.41 K/9, but beneath the surface, there exists true cause for concern.

On the spectrum of facets of Nathan’s 2013 season that are worrisome, his drop in velocity is probably the most negligible, but it is worth noting. In 2013, Nathan’s average fastball velocity sits at 91.7 mph, as compared to his average fastball velocity from 2012 of 94.0 mph. Strangely enough, hitters are only hitting at a .083 clip against Nathan’s fastball despite the dip in velocity, but this due to an incredibly low BABIP of .063 against the pitch (for reference, Nathan’s fastball has drawn a BABIP of .220 for his career). Furthermore, Nathan has shown a noticeable dip in velocity with his slider as well—average slider velocity of 85.6 mph in 2013, as compared to 88.5 mph in 2012. But what is most strange about Nathan’s slider in 2013 is not the dip in velocity, but the sudden increase in vertical break with the pitch. For his career, Nathan’s slider has exhibited a 2.8 z-MOV (z-MOV measures vertical movement, so for example, a pitcher with a big breaking curveball would post a negative z-MOV). In 2013, Nathan’s slider has shown more vertical break—0.8 z-MOV, which is completely out of the normal for Nathan’s career. What affect this will have on Nathan’s season going forward is truly difficult to tell, but it does give the indication that there is something that Nathan is doing differently, whether it be purposely or not.

Perhaps what is the most alarming facet of Nathan’s 2013 season is his declining GB%. In 2012, Nathan posted a GB% of 45.4, as compared to a GB% of just 25.5 in 2013. Nathan has yet to show difficulties when it comes to an increased rate of surrendering homeruns in 2013, but with such dips in velocity to go along with a declining GB% and career-low BABIP of .208, this recipe could ultimately lead to trouble.

What is wrong with Joe Nathan is quite simple, he’s aging and is on the decline. As mentioned before, Nathan’s 2013 season has yet to appear troublesome on the surface, but there are noticeable differences across the board. Based on these aforementioned figures, it is not a matter of how effective Nathan is at the moment, rather how long before he implodes.

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  • Eric Reining

    I agree, though I’d consider his dip in velocity much more than negligible. I think it’s his potential foil moving forward in 2013.

    Joe Nathan is still a very serviceable relief pitcher, and the fact that he’s only blown one save will probably keep the fans off his ass for the time being, but you definitely help illuminate some legitimate concerns.

    One would think he’s due for quite a spike in BABIP and home runs allowed, which at this point is only a matter of time, if you ask me.

    • Mike G.

      Yes, I agree, and if I may add one more observation, I do remember that Joe Nathan did indeed struggle towards the end of the season in 2012. I figured that Nathan’s struggles towards the end of 2012 had to do with a combination of his age, declining durability and lower velocity as compared to before in the season, but I was somewhat confident that Nathan could have a strong 2013, and on the surface he really has, but there are definitely warning signs boiling beneath that said surface.

  • Mike

    Ah, but whats the BABIP when he pitches on tuesdays @ night with the wind blowing out of the south and the humidity under 50% against switch hitters? Thats the tell tale sign.

    • Mike G.

      Smugness and sarcasm. Nice combination.

  • Andy

    Let’s hope for a swift and effective recovery for Soria, and the continued development of Scheppers.

    • Mike G.

      Scheppers has been more than impressive. I wasn’t very high on Tanner after watching him pitch last season, but he’s been fantastic in 2013. Although I would expect Scheppers to have more Ks, given his dominance and electric stuff, but like you said, the continued development of Scheppers is very important to the current bullpen and of the bullpen of the future.

      • Andy

        Absolutely. I think it’s a crime that fWAR pegs him just barely above replacement due to severely outperforming his FIPs. That’s what shutdown relievers do; they strand mistakes on base (their own and inherited runners). Peripherals be damned, Scheppers is our most valuable reliever this year so far.

        • Mike G.

          Indeed. I really hope that Scheppers can keep this up, but much of this depends on if he can keep throwing his fastball with that level of velocity, not necessarily the pitch speed. The tailing action on Schepper’s fastball during some of his outings has simply been spectacular.