Less than a year ago, Tom Murphy was catching in Triple-A Albuquerque, batting eighth for the Isotopes and wrapping up a fourth consecutive season in which he failed to register 100 big-league plate appearances. Now platooning with Omar Narvaez in Seattle, Murphy’s .366 wOBA is sixth among big-league catchers with as many trips to the plate, and he has past the century mark on that count two weeks before the 4th of July. Since June 1, he’s hit five home runs for the Mariners, matching his career high for a single season in a month that’s not over yet.

To hear Murphy tell it, his sustained success in the major leagues this year — he’s always been a good Triple-A hitter — has been driven by three major adjustments, made meaningful by the opportunity he’s getting to play so often. The first is to the pitches he’s hunting. The second is to the way his upper body helps him get to those pitches in time to make contact. The final adjustment is to the physical foundation that lets him do damage when he makes contact.

During his first four seasons in the big leagues, Murphy swung at 74% of the fastballs he saw up in the zone (64 of 86), which was about the same rate at which he swung at fastballs in the middle and bottom thirds, too. (He swung at 70% of those pitches, or 116 of 165 he saw.) This year, by contrast, he’s swinging at pitches in the top third nearly 81% of the time (34 of 42 pitches), and pitches in the bottom two-thirds just 64% of the time (63 of 99). That’s the first adjustment.

But just swinging at different pitches won’t make much of a difference if you can’t hit those pitches when you try to. Murphy told me that this off-season, he switched from taking pitches off a tee to training off an Iron Mike pitching machine almost exclusively. The resultant change in training velocity — from literally zero to something more closely approximating game speed — exposed what, to Murphy, had become an unhelpful amount of “slack” in his upper body.

“When I would go to swing in previous years,” he said, “I wasn’t at my end ranges of muscle activation or joint manipulation, or any of those sorts of things. So when I would go to swing, I’d have to take the slack out of my swing before my barrel would start. Whereas now, I’ve worked to take the slack out of my swing before that pitch ever leaves a pitchers’ hands and so now, when I’m deciding to swing, I’m already in a position that I can just drive towards the pitch.”

Take a look at some of Murphy’s swings from last year, and you can see what he’s talking about. Here he is last August, late on a 90 mph cutter from Wade Miley, in part due to the slight pull back in his upper half that occurs after the pitch has been released:

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Compare that swing to these two from earlier this month, both of which resulted in home runs. During both, Murphy draws his upper body back before the pitch is released. As a result, all of Murphy’s movement after the point of release is towards the pitch, not away from it. Murphy wouldn’t get into the details of the biometric consequences of this adjustment, but he assures me that the Mariners’ numbers suggest his muscles are now — I suppose the phrase would have to be — substantially more activated.

Murphy tells me that getting his body ready to hit before the pitch is released has helped him to make the most of a slight change in bat path — suggested by hitting coach Tim Laker, and common to a number of Mariners hitters — intended to keep the barrel of the bat in the zone longer. Put the two together, and you get the marked improvement he’s seen in contact rate on pitches inside the zone (from 73% last year to 88% in this one).

With those two changes alone, Murphy might be choosing better pitches to drive — those fastballs up in the zone — and making contact with them more often, but he also might still be hitting them into the ground, which wouldn’t really help things much. Last year, Murphy hit groundballs nearly 46% of the time, and for a player who runs like the catcher he is, that just wasn’t going to cut it. This year, Murphy’s groundball rate is down to 37% and his fly ball rate up to 42% from last year’s 34%. Nearly a quarter of those fly balls have become home runs. Murphy again credits the change to Tim Laker. But it didn’t come easy.

“That lower half adjustment was a bit of a struggle at first, a fight,” says Laker. “It wasn’t something that came natural to him. When he first got here he sat back too much and therefore had a hard time going forward — he’d go too far forward when he did. And what you want instead is that ‘50-50’ athletic position where you’re a bit more balanced on both feet. Now when he goes forward he’s able to make an aggressive move towards the ball, yeah, but he’s still staying in the ground with his legs, which means that it’s not just an upper-half swing.”

Murphy is less confident that he’s settled into this particular adjustment than the others. “I think a big thing we’ve worked on since I’ve been here is bat path,” he told me. “My lower half” — a pause here — “is just ok. It fluctuates between being good sometimes and other times, not so good. I know if my path is doing well, I have a better chance. But when that lower half is going good it means I can take those pitches up in the zone and turn them into line drives. And even when I make a mistake on those ones, it’ll be a fly ball that I pull. And those turn into home runs.”

Whether or not it sticks, one thing is clear: Murphy is putting in the work to make the most of the opportunity he’s been given with a Seattle team in rebuild mode. “As a hitting coach, you pull for guys like Murph,” says Laker. “He’s probably the hardest-working guy we have on the team. And I know he’s had success before in Triple-A, but for me, seeing him have that success here in Seattle, and knowing I had a tiny little part of it, is pretty cool.”

Unlike, say, teammate Daniel Vogelbach — who shows a pronounced platoon split — Murphy hits about as well against righties (against whom he has a 138 wRC+) as lefties (134). So too does platoon partner Omar Narvaez (131 vs. 149), which has meant that manager Scott Servais has used the two men about evenly for the last month or so. That’s in contrast to the early part of the season, in which Narvaez was the clear starter, with Murphy in a backup role.

Murphy is fully aware of how much his performance this year, and the opportunity that’s come with it, matters to the course of his life. “It means everything to me,” he said. “I’ve waited my whole career to have this kind of opportunity. The fact that I’m running out there as much as I am right now and performing at a decent level is everything. I’m sure there’s a lot of guys that end up with minor-league retirement that could have played here and were never granted the opportunity. I’m doing everything I can to make it count.”