Top catching prospects are hard to come by, and you can never have too many of them. The Rays are lucky enough to have one of the top ones in Justin O'Conner. Even though there are some things that still need to be improved upon, O'Conner has already impressed enough to be listed as the No. 7 catcher in the minors, per mlb.com's rankings.
Here is the consensus: O'Conner has the best arm of any catcher in the minor leagues. He gets out of his stance quickly and has a cannon of an arm.
Just look at the video below, one of the few we have. Byron Buxton is one of the fastest players in the minor leagues, and O'Conner guns him out with time to spare. I don't want to over-hype his arm, but at the same time I really want to because I have not seen anything like it in a long time.
This year, he threw out 48% of the guys who tried to run against him. If nothing else, his arm could take him to the majors.
While his arm gets a true 80 grade, Rays officials have said O'Conner's defense suffers because he will focus on developing one aspect of his game too much. This often leads to other aspects being forgotten about. More specifically, they have said, according to Kiley McDaniels of Fangraphs, "O’Conner has so enthusiastically taken to their framing suggestions/emphasis that he sometimes can focus too much on placing the pitch in the zone and overlook catching it."
Behind the plate, O'Conner's success rides on his ability to seamlessly integrate the different aspects of catching.While the pop time is far above average (hitting 1.7 at times), other skills need work.
McDaniels also details confidence issues in the past when it comes to his mechanics. While this is speculation, it could be because O'Conner was fairly new to catcher when he was drafted. In addition to that, he had bone spurs in both hips (not related to baseball) that required surgery to remove, so he is worried about hurting himself still. It's one of those things that only time can really fix.
The Tampa Bay coaching staff obviously wants to keep him at catcher (who wouldn't with an 80 arm), so he will get the reps necessary to integrate the different pieces of playing behind the plate while shaking off confidence problems.
In the batter's box, O'Conner often has lapses because of the aforementioned over-focusing. If he is paying attention to his bat speed, then his pitch recognition suffers and vice versa. While pitch recognition is usually something you learn at younger years, O'Conner didn't get the reps necessary to learn this skill.
When you watch O'Conner swing the bat, the raw power in his swing is apparent. He puts oomph into every swing, but he often swings too much. While in last year's Fall League his strikeout rate was quite impressive, he regressed mightily in that area, striking out almost 30% of the time at Double-A Montgomery in 2015.
It would appear that a lot of the problems with O'Conner's approach are mental. His aggressive approach comes from the faults in pitch recognition, and while physical errors are more easily correctable, they could be a lot worse. O'Conner's in-game power is projected to come after the corrections in his approach are made.
On the whole, O'Conner will most likely be carried to the majors by his arm and to a lesser extent his defense. Catcher is one of the few positions where that can happen; he has the raw tools to do so. However, the over-focusing on aspects while both catching and hitting are going to cause problems. While he has a high ceiling of a 15-20 home run catcher at the plate, he is far off from that profile.
As of now, he looks like a purely defensive catcher that'll pop a homer here and there at the bottom of your order. Next year will be his seventh season in the Rays system, so he will have to make major strides within the next year.