Over the weekend, the Red Sox promoted Blake Swihart, who was our highest-rated catching prospect heading into the year. The Padres followed suit two days later by promoting another highly-touted minor league catcher in Austin Hedges, who ranked 130th overall on Kiley McDaniel’s pre-season list, but was rated much higher by most other outlets. All indications are that Hedges serve as the Padres backup catcher behind Derek Norris, who seems unlikely to be benched after his excellent .323/.343/.500 start to the year. Hedges made his big league debut on Monday by striking out as a pinch hitter in the 9th.

Although they’re both well-regarded catching prospects, Hedges is a much different player than Swihart. Swihart is a plus defender with an interesting, but still-developing bat. Hedges, on the other hand, is widely considered to be one of the best defensive catchers on the planet, who offers very little in terms of offense. Through the end of the 2014 season, Hedges owned a .251/.311/.378 batting line in the minors, which earned him a 91 wRC+. This was bookended by a wimpy .225/.268/.321 (67 wRC+) showing in Double-A last year.

Despite these struggles, the Padres opted to challenge Hedges by having him open the 2015 season in Triple-A. He adapted surprisingly well. In 21 games in the PCL, he hit a loud .324/.392/.521. Obviously, this a tiny sample, but the signals emerging from this tiny sample were good. Hedges walked exactly as often as he struck out, and also hit for power in his month against Triple-A pitching. He came nowhere close to doing either of those things in Double-A last year.

This mini breakout, along with Hedges’ defensive prowess, was apparently enough to convince the Padres that he’s ready for the big leagues. Or at the very least, it convinced them that he’s significantly better than Wil Nieves, who boasted a 28 wRC+ before he was DFA’d. Whatever the reason, Hedges, who’s all of 79 plate appearances removed from a .589 OPS season in Double-A, is now a big leaguer.

As good as Hedges’ batting line was in the minor leagues this year, you can still find flaws if you look closely enough. While the results have been good, Hedges’ plate discipline is pretty terrible according to Minor League Central’s zone and swing data. Hedges has swung at an alarmingly high number of pitches outside of the strike zone, and hasn’t exactly balanced it out by swinging at a ton of pitches inside of it. His O-Swing% was among the highest in Triple-A last month, while his Z-Swing% was only slightly higher than average. The 2015 Triple-A averages are demarcated by the yellow lines in the chart below.

It’s worth noting that minor league zone data is recorded by stringers, which makes it less than super accurate. But even so, it’s hard to believe that Hedges’ position in the far right of this chart is entirely a fluke. And it really seems that way when you consider that Hedges was similarly far from the pack in Double-A last year.

While exciting, Hedges’ hot start in Triple-A isn’t what got him to the majors. It helped, sure, but it’s his glove that made him a consensus top 150 prospect and it’s his glove that will generate nearly all of his value going forward. Hedges’ defense grades out as excellent across the board. Kiley gave him future values of 60 and 70 for his fielding and throwing respectively, and called him “one of the best defensive catchers to come through the minors in years.”

The data agree with this assessment. Hedges threw out a respectable 38% of would-be base stealers in Double-A last year, but it was his pitch framing that really tipped the scales. According to Baseball Prospectus’ minor league framing model, Hedges earned his pitchers 37 more strikes than the average catcher last year. This was the best minor league framing season on record, and was far and away the highest mark among minor league receivers last year.

Given his defensive prowess, Hedges won’t need to hit very much to be a net positive for the Padres. The offensive threshold for catchers is extremely low, and it’s even lower for crème de la crème defenders like Hedges. This explains how Jeff Mathis, Jose Molina and Chris Stewart managed to stick around so long. But even if he’s Ivan Rodriguez 2.0 behind the plate, Hedges will need to hit at least a little bit to be anything more than a backup, and it’s not at all clear he’ll be able to do that. Kiley quoted one insider in his Padres write up who said Hedges was “more like Drew Butera than people want to admit.” Yuck.

KATOH isn’t a fan of Hedges based on his 2014 stats. My system pegs him for 1.2 WAR through age-28, which is downright awful. To be fair, the current KATOH model does not directly account for defense, which certainly underrates excellent defensive catchers like Hedges.

Since KATOH isn’t a ton of help, let’s pull up some comps. Using Hedges league-adjusted stats and his age, I calculated the Mahalanobis distance between Hedges 2014 season, and every Double-A season since 1990 in which a player recorded at least 400 plate appearances. Below, you’ll find the historical players who were nearest and dearest to Hedges 2014 campaign by this methodology, ranked from most to least similar.

Since the offensive requirements for big league catchers are vastly different than those for other positions, I included a second table that only considers players who made the majority of their starts at catcher.

*Batters who have yet to play their age-28 seasons

Of course, this isn’t to say that Hedges will be as crappy as the players on these lists. Hedges’ biggest calling card is his defense, which isn’t really accounted for in these analyses. Even when limiting the pool of players to catchers, guys like John Buck, who’s a poor defender by most accounts, still find their way onto the list. Nonetheless, these lists should give you a general sense of the type of hitter Hedges will be: A poor one.

All in all, this call up seems a little curious. Even if he doesn’t hit, Hedges’ defense will probably make him a net positive for the Padres, but it’s hard to envision him being much of a net positive, especially if he’s only playing two or three games a week. Perhaps more importantly, there’s the issue of Hedges’ development. As the team’s backup catcher, he’ll spend a lot of time sitting on the bench. That’s time that would likely be better spent getting reps in the minors, and learning how to decipher good pitches from bad. But for better or for worse, Hedges is a big leaguer. And the Padres now have a backup catcher who’s a defensive stalwart, which makes them a better team than they were yesterday.