1. The Padres will never sign a premier slugger and have historically had difficulty developing hitters
Let's get the most obvious issue out of the way first. Even if the Padres could sign a free agent as impactful as Kemp, they probably shouldn't. The Padres are generating more revenue these days, but their spending power is still dwarfed by the top clubs in the free agent market. Marquee clubs like the Yankees, Cubs, and Red Sox have larger markets to generate revenue from and thus have the budgetary flexibility to withstand the decline/overpay years inherent in every elite free agent's long-term contract. This is usually a non-starter in free agent talks, but you would have to also figure that Petco's notoriously difficult hitting environment and a lack of perceived prestige in the Padres franchise would be another roadblock for bringing in top offensive talent.
When a team can't sign hitters it must develop them internally or acquire them via trade. It is too early to know whether or not the Preller (or even Byrnes) administration has improved on the club's historical difficulty producing offensive talent. Those seeds are still growing. However, we know that the best offensive talent in the system is either too far away (Renfroe, Turner, Gettys) or too uncertain (Liriano, Peterson, Spangenberg) to provide instant offense to the big club. The Padres' ineptitude on offense last season prompted a more grievous suicide watch than the marriage of George Clooney. Seth Smith is a fine offensive piece, but is victim of a nasty platoon split and more of a quality contributor than an offensive cornerstone. Beyond him there is a major dearth of hitting talent and virtually no bats to build around. The 2014 Padres offense was bad, but the core offensive outlook seemed even worse.
2. Matt Kemp was one of the most productive hitters in baseball last season and at times carried his team offensively
Looking at outfielders age 30 or younger, Matt Kemp was behind only franchise cornerstones Mike Trout, Andrew McCutchen, Giancarlo Stanton, Michael Brantley, and Yasiel Puig in terms of total offensive production via wRC+. His second half was the stuff of legend - where he was worth 70% more than the average MLB hitter. His play carried the Dodgers through Hanley Ramirez's injury and Yasiel Puig's slump.
Kemp is a top-20 hitter in the game. Looking at full-time players (min. 400 PA), the Padres had just five of the top-200 hitters in baseball - of course that number doesn't specify that they had just two of the top 189. Kemp's offensive production above replacement level was actually higher than all of the Padres' positive contributors combined. The Padres obviously need offense in the worst way. Kemp is undoubtedly a negative on defense, but his defense isn't as bad as it appears at first glance since his statistics in center field drag down his already unimpressive body of work. A full-time move to his natural position should facilitate some improvement in his defensive numbers, but he won't be an asset in right field either. GMs have been placing more and more value on defense in the last several years. However, the simple WAR calculation and our set of defensive metrics are problematic. While defensive metrics are of course based on some level of objectivity, they are nonetheless more of an abstraction than traditional stats which have ironclad outcomes and measurements. More than that, defensive stats are less within the player's control because they have no influence over the volume/difficulty of their chances or the defensive alignment. While Kemp does not pass the eye test as a "good" outfielder, the severity and impact of his defensive problems are difficult to fully comprehend.
It is worth noting that the Padres' two most fly-ball-prone pitchers from last year (Stults and Kennedy) are unlikely to return in 2015 and beyond.
Though moving to right field should pick up his defensive marks to some degree, the aging and injury process will surely rob him of some range. Kemp has an awful first step due to poor reads on the ball, but he can still get up to speed relatively quickly and has good closing speed for a guy his size. Though he battled injuries in 2012 and 2013 they were of the decidedly fluky variety (an awkward slide and an outfield collision). Ankle injuries tend to recover better than foot, knee, hip, or hamstring issues, and Kemp's shoulder seems to be fine after posting strong power numbers in 2014 and gunning down 7 runners from the outfield. Physically, he projects to be in fine condition to play corner outfield for the next few seasons without a huge physical dropoff. The bulk of his defensive problems are non-physical (i.e. potentially even fixable if Kemp works as hard to improve his defense as he did his baserunning).
WAR, what is it good for? WAR/$ is obsolete
Otherwise we could just place an order at the WAR factory, or go to the WAR section at Costco, get a hundred-pack of WAR and go on to one of the most dominant winning stretches of all time.
The so called "market value of WAR" is a handy reference. It quickly sets the ballpark for determining if a contract has positive or negative value. However, the equation (typically around $6m per win) is upsettingly linear and has no adjustments for scarcity, demand, or contract length - i.e. the literal bases of analyzing economic utility in every other marketplace in the world. Hypothetically, we can say that Robinson Cano projected for 5.5 WAR in 2014, then minus half a win every year until the end of his contract - that would peg him at around $200m of market value. However, market value calculations are worthless when we know a player's actual market value. The market determined that Robinson Cano was worth $240m as a free agent - a 20% premium over his calculated market value. The trend in the baseball blogosphere has been to say that this type of deal is an "overpay," but these numbers are then used to help judge inflation in MLB salaries for the next WAR/$ calculation. Market value is determined by how much the market is willing to spend on an asset, not the other way around.
Players like Cano (or Kemp) don't come along very often - and when they do, teams wife-them-up immediately. Teams have learned to lock up their young talent early in order to buy out free agent years and avoid paying for decline years. Impact players are now far less likely to reach free agency in their useful years. Remember those top producing outfielders under age-30? None of them are reaching the open market while still near their primes, and if they do they will require contracts that heavily overpay their decline years.
If Matt Kemp was a free agent tomorrow, his deal would probably take him deep into his late-30s. Even if we use a WAR-based regression model for a player's decline, we can't account for a "market value" contract length. For a comparable, Nelsom Cruz just secured a contract that will pay him through his age-37 season and will primarily DH throughout the contract. Kemp is under control for the next five seasons, but will only be finishing his age-34 season at contract's end. The $15m AAV is comparable to what the Mariners are paying for Cruz's next four seasons - seasons that will almost surely include a precipitous drop in Cruz's power. Power is almost always the first batting tool that dies in a hitter, but it usually doesn't drop off until a player hits his mid-30s (roughly half of the top-20 power hitters by ISO are 30 or older, many guys on the cusp are 32 or older). Though the Mariners should be concerned, the Padres are unlikely to see enough of a drop off in Kemp's power to keep him out of the middle of the batting order during this contract. The situation that allows for Kemp to be had at below market rates is the Dodgers' previous mismanagement of their outfield depth. There was a logjam of high-priced outfielders and LA is being forced to move one of the two that have actual value.
Power, particularly right-handed power is both scarce and valuable. Teams value it because of variables that don't show up in reference stats like WAR. Matt Kemp in the on deck circle can force a pitching change. Matt Kemp can get Seth Smith or Jedd Gyorko more pitches in the strike zone. Matt Kemp keeps players from mentally checking out when the Padres fall to an early deficit. Even if you don't believe in "intangibles" in the sports cliché sense of the word, you have to concede that WAR doesn't perfectly capture or weight all the variables that go into a star player. The formula will always be somewhat arbitrary when held against actual market value.
4. The now and future catching situation
If you're like me, you're probably sick of hearing about how Austin Hedges is the Chuck Norris/Bacon/Double IPA/Crossfit of catching prospects. The internet won't shut up about him despite the fact that he's made no noticeable impact on any of our lives. While I am bullish on the receiving skills of a catcher who was said to be ready for major league action straight out of high school, he still has a lot to prove with his bat. Thanks to his defense, he will almost certainly find his way onto a big league roster at some point, but it remains to be seen exactly what kind of a contributor he could be. With the aforementioned difficulty in developing impactful position players, it seems the Padres will take the long view and hope Hedges can become a complete player and a Petco mainstay for years to come.
In the meantime there is Rene Rivera, who is penciled in to start on opening day. The 31-year old journeyman seems to have found a place of belonging in the Padres organization. Staff ace Andrew Cashner adopted him as his personal catcher. Tyson Ross also turned in his best work with Rivera behind the dish, struggling at times to get on the same page with Nick Hundley and Yasmani Grandal. Behind the dish Rivera was clearly the best defender and thrower of the three Padre backstops. As an elite pitch-framer and good handler of the staff, Rivera had a sparkling 3.17 catcher ERA - best of any player who caught as many games as he did. An asset behind the plate, Rivera was also one of the team's best hitters last season thanks to an unexpected surge in power. Moving forward however it would be hard to project him to do much better than his career average line: .228/.279/.358.
If Rivera hits just passably moving forward then he and similar defense-first backstop Tim Federowicz should be a useful duo behind the dish in 2014, buying time but not blocking the Padres' top prospect. Grandal is much closer to his payoff than the 22 year old Hedges, but if they were to both have strong 2015 seasons, the Padres' leverage would greatly decrease in trade talks. Since both can't catch at once, one would have to be moved in order to get fair return for talent. The worst kind of move a team can make is the one it "has to" make. Hedges' upside represents the kind of risk that an organization like the Padres must be willing to take.
5. The problem with Yasmani Grandal
Grandal had a tumultuous tenure with the Padres. Trades, PEDs, a feud with Nick Hundley, a catastrophic knee injury - Grandal has looked like a star and a scrub in just a few years in San Diego. After three years there is still a lot we don't know about what kind of a player he is and what he will become. We know he controls the strike zone very well - both from the batter's box and behind the dish through his plus pitch framing. We know he will never move well defensively or on the basepaths. We know he has some power. We know he doesn't look as goofy at first base as Will Venable.
That's pretty much it. The guy who hit .297 as a rookie has hit .216 and .225 since. His walks are still up, but the strikeout demons he battled in the minors have come back with a vengeance. 26% of Grandal's plate appearances in 2014 ended with "strike three." Nobody in baseball walked as much as Grandal while getting on base less. Grandal was picked by many as a breakout candidate for 2015 because the keys to Grandal's offensive game are all present. The part we take for granted is actually hitting the ball, which he hasn't yet shown he can do consistently. He particularly struggled with breaking pitches, which pitchers used to finish him off when his patient approach set him behind in the count. Even when you average in his 2012 to try to counterbalance his injuries you're looking at a .245/.350/.412 batting line - certainly respectable, but hardly lineup-changing for an offense-minded catcher.
A discussion of Grandal is incomplete without discussing his surgically repaired knee. In the sports medicine world there are three kinds of lower body injuries: 1. Injuries. 2. Knee injuries. 3. ACL tears. Even without a comprehensive survey, you can say with relative certainty that ACL tears have ended more football, baseball, and basketball careers than any other kind of trauma. To put it in Padres terms - ACL tears are the lower body equivalent to Tommy John surgery. Already an iffy defender, Grandal is now even less mobile behind the dish than he was pre-injury. Catcher is easily the hardest position on a player's knees, and unless Grandal breaks into a much much better hitter, his value is tied to staying at catcher. Couple this with a guy who isn't winning any popularity contests, you have to consider moving him before he has a chance to prove the hype wrong.