Back in April, the Padres put the finishing touches on their 2015 team, trading for one of the best relief pitchers on the planet in Craig Kimbrel. They didn't give very much to the Braves, sending them only two mid-level prospects and a pair of obsolete outfielders. Rather, as I wrote at the time, San Diego had to take on an unsightly contract: the three years and $46 million owed to B.J. Melvin Upton. Atlanta had inked him two years prior, hoping he'd anchor their outfield for the next half-decade; that didn't happen, as his putrid play made him a completely useless player.

Perhaps signaling a change of course from last year, the Padres dealt Kimbrel to the Red Sox on Friday. The deal brought quite the return, but it still left San Diego without its relief ace. Now, the only player remaining from the initial swap is Upton, a sunk cost. Like many of the 2014 offseason's transactions, this one won't help the major-league club at all in 2016.

Or will it? Upton certainly hit horrendously as a Brave, with a 66 wRC+ over 1,028 plate appearances. As a Padre, however, he held his own: In 228 trips to the dish (obviously a small sample size, but not without its potential signals in the noise), he pounded out a 110 wRC+. That actually surpasses the 107 mark that he posted with the Rays, his employer before the Braves. If Upton can indeed recapture that magic — and the changes he underwent in 2015 make that a plausible outcome — he'll give the Friars another solid outfielder for the last two years on his contract.

Upton didn't lack walks in Atlanta, taking a free pass in 9.8 percent of his plate appearances — a figure that he roughly matched in San Diego. His improvement came in the other three areas of offense, where he completely returned to form:

Team (Year[s]) K% K%+ ISO ISO+ BABIP BABIP+ Rays (2004-2012) 25.1% 138 .167 110 .322 108 Braves (2013-2014) 31.5% 156 .116 84 .277 93 Padres (2015) 27.2% 133 .171 114 .348 116

2015 Upton put the ball in play much more often, with far greater authority, than 2013-14 Upton did; he also did so to just about the extent that 2004-12 Upton did. Let's dive into each of these metrics.

Regarding Upton's strikeouts, we should first note the different versions of Upton that resided in Tampa Bay — specifically, the 2012 iteration. That campaign saw him go down on strikes 26.7 percent of the time, not very different from the years before, but the manner in which pitchers fanned him had changed. Heading into that year, he owned a career* zone-swing rate of 63.9 percent and a swinging-strike rate of 10.4 percent, via FanGraphs' PITCHf/x data. Both of those shot up dramatically in 2012, when he offered at 73.0 percent of pitches in the strike zone and whiffed at 15.1 percent of the pitches he saw. In other words, he took far fewer called strikes, while accumulating many more swinging ones.

*From 2007 on - PITCHf/x data.

On his travels to Atlanta, the whiffs didn't go away, and the looks came roaring back. Upton swung-and-missed at 15.3 percent of his pitches with the Braves, while defending the strike zone just 65.6 percent of the time. This unappetizing combination — the worst of both worlds, essentially — made Upton by far the most strikeout-prone player in the league during that time, sucking away a good deal of his value.

With that said, all was not lost. After he came to San Diego, Upton went back to his original recipe — i.e., his 2012 one. For the Padres, he posted a 72.9 percent zone-swing rate, along with a 15.3 percent swinging-strike rate. While the latter meant that he still didn't make much contact, the former ensured that he'd do so frequently enough to stay afloat.

In which areas did Upton assert himself? Dividing Brooks Baseball's strike zone into three vertical strips, we see a pretty clear trend:

Team (Year[s]) Inner Swing% Middle Swing% Outer Swing% Braves (2013-2014) 69.7% 78.0% 65.1% Padres (2015) 70.1% 84.1% 65.3%

Upton maintained his comparative hesitance on inside pitches, in addition to outside pitches. The ones down the middle he didn't let pass. By swinging at those sorts of pitches, he cut down on his strikeouts and rejuvenated his offense.

The other two metrics — BABIP and ISO — are, inherently, more fluky. Whereas a hitter will receive thousands of pitches across a full season, he'll generally put wood on bat only a few hundred times, at most. In Upton's case, he totaled 140 balls in play in 2015, which makes for an uninspiring sum. Nevertheless, the trends within those make for an intriguing case (and a fairly convincing one).

Upton's line drives comprised 24.3 percent of his 2015 balls in play. That easily tops his career 18.1 percent figure, as well as his 18.4 percent level from 2013 to 2014. Perhaps more importantly, he put the ball on the ground only 41.4 percent of the time, finishing below his lifetime clip of 44.1 percent and his Atlanta mark of 44.0 percent. Although 7.1 percent of his balls in play were of the infield fly variety, a rise in liners and a drop in grounders compensated for the popups.

Oddly enough, Upton didn't make more solid contact this season (32.4 percent hard-hit rate) than he did in the prior two seasons (32.6 percent). The difference lies elsewhere, in his batted-ball distribution. 50.3 percent of Upton's 2015 balls went to left field, compared with 40.0 percent over his major-league tenure. Like the vast majority of hitters, he's always performed the best when yanking the ball, with a .293 career ISO and .346 career BABIP on such hits. Those numbers didn't budge at all in 2015, as Upton notched a .292 pull ISO and a .343 pull BABIP. He's simply decided to go that way more often, and the results speak for themselves.

Upton's aforementioned swing patterns illustrated his somewhat-patient approach to inside pitches. That seems to have paid off, because that's where Upton did most of his ISOing...

...in addition to the majority of his BABIPing:

This syncs up with the Tampa version of Upton, who always hit for the most average and power on the pitches closest to him. Inside pitches will more readily travel with his swing, heading to the area of the field where Upton inflicts the most damage.

Pulling the ball this often leads us to wonder if opposing teams will shift on Upton. Three factors would work against that, though. Upton hits right-handed, which makes shifting more difficult; he didn't hit many ground balls this year, which the shift tends to most effectively counter; and he didn't fare especially well on those ground balls to begin with, putting up a .190 grounder BABIP. All in all, it doesn't appear that new-fangled defenses will deter Upton.

The progress in contact quality may inspire some skepticism, and it should. Line drive rate vacillates wildly from year to year, as do the descriptive statistics it impacts. It's entirely possible that this efficacy was simply a mirage, and as such will vanish over a full season's worth of playing time in 2016. But it definitely looks as though Upton has rediscovered the stroke that he had lost. At age 31, he may have finally gotten his career back on track.

Most of the Padres' moves last offseason didn't turn out especially well. Matt Kemp, Derek Norris, Will Middlebrooks, and James Shields all flopped in San Diego, to varying degrees. Justin Upton did quite well for himself, but he'll likely sign elsewhere soon, leaving behind a mere draft pick as compensation. Kimbrel and Melvin Upton stood out as arguably the two biggest positives to emerge from 2015; the former granted the team several captivating prospects for the future, and the latter can assist them for the present.

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Ryan Romano is an editor for Beyond the Box Score. He also writes about the Orioles on Camden Depot (and on Camden Chat that one time) and about the Brewers on BP Milwaukee.