On Friday afternoon the Padres agreed to a long-rumored deal with Chicago that sent Anthony Rizzo and Zach Cates to the Cubs for Andrew Cashner and Kyung-Min Na.

Rizzo had become somewhat of a surplus for the Padres after the acquisition of Yonder Alonso – a player they prefer as a fit with their club – but many were convinced they’d hold onto him incase the combination of Alonso and Jesus Guzman scuffled.  Unfortunately for the Padres every other team realized this surplus, degrading Rizzo’s value past a point many expected.

While he did struggle in 128 at bats in the majors last season, Rizzo is still widely regarded as a Top 50 prospect in the game.  Yet, that extended cup of coffee in San Diego did reveal a few facets of Rizzo’s game that were underdeveloped.

His 30.1% strikeout rate was considerably higher than what we’d seen in his minor league career, mostly caused by swing flaws that were exposed against premium velocity.  Consider the data below courtesy of Baseball Prospectus’ Bradley Ankrom:

< 90mph – 95 PA, .149 AVG, 25% SO
< 92mph – 116 PA, .132 AVG, 27% SO
>= 92mph – 42 PA, .125 AVG, 38% SO
>= 94mph – 21 PA, .063 AVG, 50% SO

While you can argue that just about every major leaguer struggles with elite velocity, MLB averages fall well above Rizzo’s 2011 results.  Even in a small sample size the numbers above have to serve as a pretty big warning sign for Rizzo’s future that obviously weighed heavily on the mind of Byrnes and the rest of the front office.

Rizzo’s dominance of Triple-A was impressive, but any scout will tell you the pitchers you see at that level often pitch backwards – meaning they lead with their developed off speed pitches and fall back on below average fastballs – which proved to be detrimental to Rizzo as it obviously did not help his development by failing to expose the flaws in his game.

Cates was one of several flame-throwing pitchers added to the Padres’ system over the last three years and pitched better in 2011 than his counting statics showed.  Cates’ addition in this trade is curious, as on the surface you’d think Rizzo had enough trade value to obtain both Cashner and Na.  Although he’s raw, Cates is much more than a throw in piece to make a trade happen, which may speak to just how much of a hit Rizzo’s market had taken over the last few weeks.

The New Padres

As recently as the beginning of the 2011 season Cashner was considered a breakout candidate for the Cubs.  Of his 48 career minor league appearances, Cashner appeared as a starter in 42 of them yet was used strictly out of the bullpen as a high-velocity reliever to start his MLB career in 2010.

His arsenal at that point featured mostly fastballs (68.7%) and sliders (23.1%) with a few changeups (8.2%) mixed in.  That repertoire led to poor results against lefties – .300/.404/.500 in 94 plate appearances – and a mandate to develop his changeup during the offseason.  Cashner looked great in Spring Training and won a spot in the Cubs’ rotation to start the season before heading to the disabled list after his first start with a shoulder strain that cost him about five months of the season – an injury the Padres claim to have little worry about.

Unfortunately, his 2011 righty-lefty splits were too small of samples to make any sort of conclusions with, but Cashner did manage to show an improved arsenal of pitches.

That collection of pitches now grades out as a fastball that can touch 100 with full rest but will sit at 95-98 when he comes out of the bullpen and 92-96 if he is asked to start, a wipeout slider that sits in the upper-80s and a much-improved changeup that often showed as plus in his brief Arizona Fall League stint.  That combination should mean that the Padres just acquired one of the best young relievers in the game, with the obvious caveat surrounding the health if his shoulder.

One side note on his time in the AFL: don’t worry about the rough-looking results, health and continued development of his off-speed stuff was his primary goal while in Arizona.

Cashner’s role in 2012 will strictly be as a bullpen arm with a chance at being a swingman if the organization is truly confident in his health.  Unless he cements himself as a frontline reliever and the starting rotation is crowded by the graduations of guys like Robbie Erlin, Joe Wieland and Casey Kelly, expect for Cashner to be given a shot at starting by 2013.

Kyung-Min Na is a player that Byrnes had been interested in since his days with the Diamondbacks.  Na offers impressive defensive instincts for a 20-year-old and well-above average speed to go with a discerning eye at the plate and an innate ability to make contact.

Byrnes has already said that he sees Na as an exciting project that needs to add more muscle, but with his slight frame it’s doubtful that he should ever be expected to be more than a slap hitter.  His ceiling probably sits around defensive-minded centerfielder/leadoff hitter with a more likely outcome as a fourth outfielder.

Na has yet to play extended time at a level truly indicative of his talent so don’t be surprised if his season begins in Fort Wayne or even Eugene if the Padres are looking to build up his confidence.

At this point it’s tough to rate this trade too highly.  While the Padres dealt from an area of relative strength, they still traded away one of their top prospects for a recently injured pitcher and a relatively low-ceiling secondary piece.  If Cashner becomes a lights-out reliever – or Rizzo becomes more of Adam LaRoche than Ryan Howard – this trade will lean towards the Padres favor, until then the upside of this deal feels like a lateral move at best.