You might have noticed that Travis d'Arnaud received some attention lately. Eno Sarris pegged him as a potential breakout slugger in a piece analyzing how often young hitters see fastballs over at FOX Sports, and Rob Parker of Fake Teams wrote that d'Arnaud has the skills to "pull off a Devin Mesoraco-type breakout in 2015."

Statements like these can only be exciting to a Mets fan. The team will almost certainly have a solid rotation in 2015, and the Mets will need players like d'Arnaud to step up if they want to compete for a playoff spot.

After long being praised as a top prospect and having a big second half in 2014, "TdA" will enter his third season in the major leagues at the age of 26. This will probably be his first full year with the big club, after playing 31 and 108 games in 2013 and 2014, respectively. Since players are supposed to enter their peak at either 25 or 26 years old, it's worth taking a look at d'Arnaud's production in the second half of last season and examining whether he can sustain or even improve upon it next year.

Plate discipline: A work in progress

d'Arnaud struggled with the bat in the first half of 2014, posting a .189/.277/.269 batting line and resulting in the Mets sending him down to Triple-A after 257 plate appearances. The coaching staff in Las Vegas told d'Arnaud, more than anything else, to simply trust his swing. George Greer, the hitting coach, also moved d'Arnaud closer to the plate so that he could better cover outside pitches.

The result was everything the Mets could have hoped for, as d'Arnaud produced a 253 wRC+ with the 51s, and then a .272 batting average and an .805 OPS after being called back up to the majors.

You can see on the two Brooks Baseball heatmaps above the difference in d'Arnaud's batting average from the first half of the season to the second. As the charts demonstrate, d'Arnaud improved his batting average against pitches both inside and outside the strike zone.

To see how his approach at the plate changed over the last two years, let's examine Fangraphs' PitchF/X Plate Discipline data:

Season O-Swing% Z-Swing% Swing% O-Contact% Z-Contact% Contact% 2013 21.80% 63.40% 43.10% 56.30% 87.10% 79.50% 2014 26.30% 67.90% 48.10% 69.10% 87.90% 83.00%

While d'Arnaud's 2013 stats are based on only 31 games and 113 plate appearances, these numbers clearly show an evolution in the catcher's hitting process. In short, d'Arnaud has become more aggressive at the plate. He is swinging at more pitches both in and out of the zone, and is making more contact on those out of the zone, as his O-Contact% indicates. The catcher's change in approach, unsurprisingly, occurred after his return to the majors in the middle of last year. Indeed, it's striking how dramatically his walk rate plummeted over the course of the year, and how he struck out at a much lower rate despite swinging at more pitches:

Year Half BB% K% 2014 First 9.50% 18.10% 2014 Second 5.70% 12.30%

In the second half of 2014, d'Arnaud started swinging at a lot of pitches and put the ball in play at a very high rate. If he can work on staying aggressive in the zone while chase fewer pitches outside of it, he can improve even more as a hitter.

Batted balls: Let's go deeper!

Now that we've seen what type of pitches d'Arnaud swings at, let's look at what happens when he actually puts the ball in play.

Season Half GB/FB LD% GB% FB% IFFB% HR/FB Pitches 2014 First 0.92 18.00% 39.30% 42.70% 10.90% 9.40% 742 2014 Second 1.25 21.10% 43.90% 35.10% 11.70% 11.70% 807

While d'Arnaud hit fewer fly balls in the second half of 2014, he managed to improve his HR/FB ratio from 9.40% to 11.70%, even reaching a high of 17.20% in August. Another useful measure of a hitter's power is the average distance of his home runs and fly balls.

According to Baseballheatmaps.com's 2014 Home Run and Flyball Leaderboard, here's how d'Arnaud performed in that category last year:

Rank Name Stance Year Hits Distance Angle 122 d'Arnaud, Travis R 2014 84 280.96 0.83

As you can see, d'Arnaud ranked 122nd among qualified hitters, with an average distance of 280.96 feet. While that doesn't seem too impressive, it was in fact a dramatic improvement from his 2013 mark of 256.30 feet, according to BaseballSavant Pitchf/x metrics.

Even more encouraging, Al Melchior of CBS Sports reported in August that, "According to BaseballHeatMaps.com, in d'Arnaud's first 39 games this year, he averaged 264 feet in flyball distance, but over his 37 games since [coming back from the minors], that mark has jumped to 287 feet."

Now here's where it really gets exciting: As Mike Podhorzer of Fangraphs notes, standard deviation of distance (SDD) is actually a more revealing metric than is fly ball distance. Podhorzer explains, "What the SDD does is remind us that the same average distance isn’t necessarily created equally. A batter with a 300 foot distance might look great when trying to project his HR/FB rate, but if that average distance was the result of 150 fly balls that traveled exactly 300 feet each, a whopping zero of them are going to leave the yard and his SDD is going to be 0. If, instead, this batters alternates between 400 foot shots and 200 footers, then he’s going to hit a lot of homers. But both would average the same 300 feet. So the SDD provides some important information."

That said, according to Podhorzer's numbers, d'Arnaud's 66.10 SDD was the 12th best in the league, just behind that of players like Chris Davis (66.49), Troy Tulowitzki (66.67), and Edwin Encarnacion (66.75), and ahead of that of Devin Mesoraco (63.96). In 2013, d'Arnaud had an SDD of 52.26, according to Pitchf/x data.

Considering his improvement in this category, let's compare both his home run total and his home run and fly ball distances in 2014 to those of the top five catchers under the age of 27, by fWAR:

Name Age HR HR+FB Distance Rank Number of HR+FB Devin Mesoraco 25 25 297.50 25 84 Yan Gomes 26 21 290.65 53 104 Travis d'Arnaud 25 13 280.96 122 84 Buster Posey 27 22 278.73 143 136 Salvador Perez 24 17 269.85 219 120 Derek Norris 25 10 261.97 269 64

Despite having hit fewer home runs than four of the top five catchers, d'Arnaud ranked third in average fly ball distance. And keep in mind that he leads all of them in standard derivation of distance. Considering that d'Arnaud had a higher average distance in the second half of the season, there is reason to believe that he could get even closer to Gomes and Mesoraco in that category.

Given d'Arnaud's SDD and average distance metrics, you might be wondering why he hasn't hit more home runs. Well, the answer could be in the average angle of his fly balls.

Home runs: To twenty and beyond?

One of the above tables includes d'Arnaud's average home run and fly ball angle according to Baseballheatmaps.com. The catcher's 2014 mark stood at 0.83. What does it mean? Simply put, "-45 degrees is a ball hit on the left field line, 0 is a ball hit to dead center and +45 is a ball hit on the right field line."

Thus, d'Arnaud's 0.83 average angle indicates that the majority of his fly balls and home runs traveled toward dead center, specifically the deepest part of a baseball field. As a comparison, although he hit the same number of home runs and fly balls as did d'Arnaud, Mesoraco's average angle in 2014 was -8.03, meaning that his fly balls tended to travel toward left-center.

Thanks to the ESPN Home Run Tracker, we can easily see where d'Arnaud's 2014 home runs landed:

d'Arnaud might pick up a few more home runs in 2015 as a result of Citi Field's fences moving in. He could pick up even more if he learns to hit the ball closer to the left and right field lines, instead of to dead center, as the following numbers bear out:

Season Location AVG ISO BABIP wRC+ 2014 as R to Left .328 .280 .288 166 2014 as R to Center .250 .181 .216 91 2014 as R to Right .288 .138 .275 98

Specifically, if d'Arnaud learns how to pull the ball more consistently, he could significantly increase his power numbers and reach that 20-homer plateau. Eno Sarris actually agreed with Rob Parker's assessment of d'Arnaud when he recently wrote on Grantland that the Mets catcher could be "this year's Devin Mesoraco."

Considering d'Arnaud's potential and the progress he showed in the second half of 2014, it is almost certain that he will be a more productive hitter this year than he was last. PECOTA agrees, projecting d'Arnaud to improve as a player and even reach that 20-home-run mark in 2015.