Why Wade Miley represents unrealized potential and a continued shift in prospect valuation

Let's get this out of the way from the get go: Wade Miley wasn't acquired to be the flashy, sexy offseason acquisition to quell the issues that daunt the front of the Red Sox rotation. Instead, Miley represents something different for the Red Sox. Miley represents another pitcher similar to the mold of Joe Kelly. Both players represent young hurlers that present significant financial flexibility, room to grow and unrealized potential (to a certain extent).

The numbers for Miley don't look great from the outside. A 4.34 ERA, 3.98 FIP, 1.401 WHIP and 183 strikeouts in 201 1/3 innings pitched don't exactly jump off the page and especially given the package sent off to Arizona (Allen Webster, Rubby De La Rosa and an unknown minor leaguer), the decision to trade off promising young arms for someone who doesn't exactly possess the highest ceiling or potential to anchor a rotation doesn't seem like a move that would make a lot of sense given the current state of turmoil in the Red Sox rotation.

From the outset, it wasn't the back end of the Red Sox rotation that needed cleaning up, especially following the departure of Jon Lester to the Windy City. It was the front end of the rotation that needed some shoring up(which is the exact reason why Yoenis Cespedes are dangling out as trade bait and setting up meetings with pitchers of the James Shields ilk). There are, however, reasons why this deal makes sense on a number of levels for the Red Sox and fits within the train of transactions that general manager Ben Cherington has pulled off since the trade deadline.

To fully wrap our heads around why Cherington felt the need to go out and trade for Wade Miley, there needs to be consideration given to the multitude of factors that influenced such a decision.

Contract Situation

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Miley is a former first round pick out of Southeastern Louisiana State University and is 28 years old. Having exhausted his rookie service time during the 2012 season, Miley is arbitration eligible for the first time this offseason. MLB Trade Rumors projects Miley to make $4.3 million next season, a rate that is a bargain given the current climate of the free agent market and the cost of established starting pitching.

Given that Miley is arbitration eligible for the first time this offseason, he will not hit the free agent market until the conclusion of the 2017 season, meaning the Red Sox acquired an established major league starter with three years of team control. As of right now, the team has Clay Buchholz and Joe Kelly seemingly locked in to the rotation. Having two pitchers under team control such as Miley and Kelly gives the team the flexibility to go out and spend on a top flight starting pitcher and avoid going overboard on luxury tax penalties for the 2015 season and tying up too much money for the future.

Scouting Report

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Let's first establish what Miley is as a pitcher. On the forefront, Miley brings five pitches to the table, a four-seam fastball, a sinker, a changeup and a curveball (which is used extremely sparingly). The fastball sits around 92 miles per hour while the secondary stuff is highlighted by the slider, which is a legitimate swing-and-miss pitch. The other offerings are just about league average.

Miley's success is predicated on his excellent command, something that led to his achievements during his rookie season. Miley's first full season at the major league level came in 2012, when he made the All-Star game and finished the year with a 3.33 ERA, 3.15 FIP, 1.182 WHIP and 144 strikeouts in 194 2/3 innings pitched leading to a 16-11 record and a second place finish in the National League Rookie of the Year balloting.

Since that point, Miley has posted two solid seasons (for a back-of-the-rotation type starter). In 2013, Miley posted a 3.55 ERA, 3.98 FIP, 1.317 WHIP and 147 strikeouts in 202 2/3 innings pitched. Miley, in 2014, had a 4.34 ERA, 3.98 FIP, 1.401 WHIP and 183 strikeouts in 201 1/3 innings pitched. The most encouraging statistic with Miley, despite some lackluster peripheral statistics, is that his strikeout rate increased dramatically from 6.5 in 2013 to 8.2 in 2014 (which is something I'll expound on in just a moment).

You can't discount the fact that Miley has stayed healthy over the last two years throwing nearly 200 innings in all three of his complete major league seasons. Having a pitcher at the back end of the rotation who you can count on for 200 innings at a controllable cost is not an easily found commodity.

From a surface-level numbers standpoint, Miley looks like a starter who, as one scout put it, is a "solid back-end guy." So in a vacuum, contract and age aside, Miley looks like a starter who could help round out a solid (not yet completed) rebuilt rotation. There is, however, more to Miley beyond the numbers he's posted in the last couple of years.

Which way is Miley trending?

While Miley might not be the flashiest pitcher in the world, he's made significant progress in a variety of areas. As previously mentioned, Miley improved his strikeout rate considerably in 2014. This increase in strikeout rate coincides with Miley's decision to use his slider more frequently. Miley's use of his slider increased steadily from 9.84 percent to 14.22 percent to 16.14 from 2011 through 2013, respectively. In 2014, Miley clearly made a conscious effort to increase the use of his slider, as it jumped from 25 percent, a total increase of 8.84 percent.

The increase in slider usage can't be ignored. Miley's strikeout rate on his slider is the highest of his four major pitches. In addition, opponents hit just .216/.265/.343 on the pitch in 2014. The slider also generates the highest percentage of ground balls among his four major pitches at 59.7 percent. Miley's success is highly dependent on the generation of ground balls and with a defense that will likely be much better than the one he had in Arizona, it would not be surprising to see Miley see a marked improvement, despite a move to the American League East.

Looking at Miley's advanced statistics, the lefty's batting average on balls in play (BABIP) spiked significantly in 2014 against right-handed batters. In 2014, righties posted a .320 BABIP against Miley, a jump from his career average of .305. In addition, Miley's BABIP at home jumped from his career average of .303 to .326. Looking at these anomalous spikes in BABIP, one can expect a signifiant regression back to career norms for Miley during the 2015 season.

According to ESPN, opponents reached base at a .277 clip (via hit or error) in 2014, a jump from his career "reached-based percentage of .254. A solid Red Sox defense will likely help bring those numbers back down to career averages.

A quick look at Miley's heat map will show that, throughout his career, he's displayed an ability to keep the ball low in the zone, an attribute crucial for a pitcher who does not have stuff that can blow hitters away.

On the whole, Miley improved on keeping the ball out of the heart of the plate in 2014.

Miley also presents pretty even splits against both left-handed and right-handed hitting. In Miley's career, righties are hitting .263/.324/.422 while lefties are hitting .251/.301/.366 against the southpaw. Miley's home/road splits also present some interesting data. At home in 2014, Miley was hit significantly harder by opponents, who hit .280/.334/483 with 18 home runs in 96 1/3 innings pitched.

Those numbers change drastically for Miley on the road, where opponents hit .246/.333/.342 with just five home runs allowed in 105 innings pitched. The Diamondbacks play in a hitter's park and Miley felt the effects of playing in a home run haven.

Over the last two seasons, Miley allowed 29 home runs in Arizona, posting a 4.90 ERA while allowing just 15 on the road en route to a 3.13 ERA. To further hammer away the point, Miley's HR/9 rate at home was 1.68. On the road, that number dropped significantly to 0.43. For his career, Miley has a 1.13 HR/9 in Arizona while posting a 0.69 HR/9 on the road. To say that it's an incredibly good thing for Miley to get out of Chase Field would be an understatement.

According to ESPN, Miley represents one of 14 pitchers to qualify for the ERA title and have a strikeout rate of at least 20 percent and a ground-ball rate of at least 50 percent in 2014. Miley's ability to keep the ball down in the zone (something he displayed consistently in 2014 above his career averages) and rise in strikeout totals, coinciding with the increased use of his slider, indicates that Miley brings more to the table than the peripheral numbers suggest.

Factoring in the departure from Arizona

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In recent years, there's been an interesting trend among pitchers associated with the Diamondbacks organizations. There has been a distinct difference in performance for a couple of pitchers during their time in Arizona and in other organizations. This was most recently seen with Brandon McCarthy, who was traded to the Yankees at the trade deadline. While the same size is a little small (a little over a full season pitched at 244 2/3 innings pitched), McCarthy struggled mightily pitching for the Diamondbacks, posting a 4.75 ERA while posting a 3.78 FIP, an astounding difference of nearly a full run between ERA and FIP.

While with the Diamondbacks, McCarthy posted a .328 BABIP in 2013 and a .345 BABIP in 2014. Like Miley, McCarthy had an astoundingly high opponent's BABIP that contributed to his inflated ERA. While with the Diamondbacks, McCarthy posted a career-high strikeout rate (similar to Miley in 2014). The inflated BABIP combined with the putrid Arizona defense suggested that McCarthy outperformed the numbers he posted during his tenure with the Diamondbacks.

Once out of Arizona, McCarthy posted stellar numbers for the Yankees (in an, albeit, small sample size). McCarthy had a 2.89 ERA, 3.22 FIP while keeping a relatively consistent strikeout rate, displaying a slight dip in walk rate and posting a 1.51 WHIP.

Since being traded to Arizona from Oakland, Trevor Cahill has flopped big time. Although he had a career high strikeout rate in 2014 (slightly inflated by a stint as a reliever), Cahill posted a 5.61 ERA in 110 2/3 innings. His strikeout rate combined with his FIP (3.89) suggest that he was, like McCarthy, was better in 2014 than his peripherals indicate.

Arizona, in recent years, has had talented pitchers. Two of their biggest acquisitions in McCarthy and Cahill, however, have both flopped. The poor defense Arizona trots out clearly plays a factor, but it's fair to wonder if there's something about the ballpark or how the team is currently constructed that plays a major role in the drastic disparities between the peripheral and advanced statistics. So while the success of McCarthy post-Diamondbacks and lack thereof for Cahill in Arizona can't predict how Miley will fare in Boston in 2015, it's important to consider precedent in this case.

So what does this move show about the Red Sox?

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All of the advanced statistics indicate that Miley is a better pitcher than his record and ERA in 2014 suggest. So when considering whether or not it was worth trading two promising arms in De La Rosa and Webster for Miley, there are couple of factors that come into play.

Webster, at this point, reaching his absolute ceiling would be an arm comparable to where Miley is right now (something that some scouts would consider a near miracle at this point). While De La Rosa possesses some of the best raw stuff in the system with his mid-90s fastball and a devastating change-up, several evaluators expressed concern with the lack of development in a third pitch that would solidify his future as a starter. In addition, the lack of swing and miss on a fastball with such velocity concerns many scouts as well. De La Rosa's floor appears to be that of a solid back-of-the-bullpen arm while it's not inconceivable to see him starring as a closer in the near future.

This move, again, shows the trend within the Red Sox organization in placing stronger value in established major league talent and not the mystical unknown, unfulfilled potential of a prospect. There are clearly exceptions in this line of thinking (Xander Bogaerts and Mookie Betts are as close to untouchable as you can get and Blake Swihart is just a tier below), but the decision to acquire major league assets instead of prospects for both Lester and John Lackey (Yoenis Cespedes, Joe Kelly and Allen Craig) indicate an overall shift in philosophy that places a strong emphasis in collecting major league talent over the gamble that's inherent with the acquisition of top prospects.

Given that Miley is coming off a lackluster season, the Red Sox are seemingly buying low on his stock. Remember, the last time Cherington decided to buy low on some of established veterans, the Red Sox signed players including the likes of Mike Napoli and Shane Victorino. We all know how that season ended.

Is Miley a flashy pitcher who will replace Lester at the front of the Red Sox rotation? No, but that's not what the Red Sox need him to be. Miley's value as a trade asset coming from Arizona comes in the form of unrealized potential as a former first round pick, undervaluation due in part to poor defense and ballpark factors, consistency at the back end of the rotation and three additional years of team financial control and flexibility. That's what the Red Sox expect out of Miley.

Nothing more, nothing less.

Editorial Note: A previous version of this article said Wade Miley attended Southern Louisiana University. He, in fact, attended Southeastern Louisiana University.