Imagine a pitcher the size of an NBA big man, all arms and legs, who could approach 100 mph and mix in a dastardly breaker to boot.

That description fit Randy Johnson, and it also applies to Rays righty Tyler Glasnow. In terms of career achievements, that’s where the similarities end. Pirates fans watched their team’s former No. 1 prospect average nearly six walks per nine innings in black and gold -- first as a starter, and then as a long reliever last year.

But the Rays saw untapped potential in Glasnow when they traded the former face of their franchise, Chris Archer, for Glasnow and outfielder Austin Meadows -- and their instincts are proving correct. Glasnow, who was just named the American League's Pitcher of the Month after a 5-0 start with a league-best 1.75 ERA, looks like he could be Tampa Bay’s third ace beside reigning Cy Young winner Blake Snell and right-hander Charlie Morton. Johnson didn’t truly become the Big Unit until he improved his mechanics in his age-29 season. Glasnow, who’s had to figure out the same puzzle in aligning his 6-foot-8 frame, is still only 25.

The T stands for "tall"

Glasnow’s height has proven to be a double-edged sword. It creates a longer path from windup to release, creating more opportunities for shoulders to fly open, torsos to twist off kilter or legs to step out of line. But when every lever is firing correctly, it can overwhelm a hitter. Here were Rays manager Kevin Cash’s first impressions of Glasnow after his Tampa Bay debut last August:

"How can you not be impressed with the stuff coming out of his hand? He was 94 [mph] his first fastball, and after that, sat 96-99 mph. It doesn't look like he's overthrowing, that's just him. It looks like he's placing the ball in the catcher's mitt. He's going to be really successful," Cash said.

Cash was talking about extension with that catcher’s mitt analogy, and no Major Leaguer owns more extension than Glasnow’s 7 1/2-foot average on four-seam fastballs. By releasing the ball closer to home plate than anyone else, Glasnow’s high-90s fastball looks like 100-plus to a hitter’s eyes. That’s the enviable tool that Glasnow started with, the one that made him a desirable trade asset in the first place. But after working with fellow 6-foot-8 human Kyle Snyder, the Rays’ pitching coach, Glasnow seems much more aware of how to use that heat.

"My agent texted me, a couple of people were like, 'Man, your pitching coach is 6'8", so that'll be great,'” Glasnow told the Tampa Bay Times last summer. “[Snyder] is one of the more knowledgeable pitching coaches I've ever had."

Once Glasnow arrived in Tampa Bay, Snyder began encouraging the fireballer to start letting his fastball go.

“I tried to express to him that he could be really aggressive in the strike zone,” Snyder told FiveThirtyEight last month. “The guy is 6-foot-8. He throws the ball from 52 and a half feet [from home plate]. He’s an upper 90s guy. It’s an all-power, no-art approach. I just think the more he understood that the hitter in the box had to respect the fastball and cheat to it, the better the breaking ball was going to be.”

Glasnow echoed that sentiment Thursday to MLB.com’s Juan Toribio, stating that a change in his mental approach has allowed him to let his natural tools take the lead again.

“I was very obsessed with the feeling of being perfect and trying to find like the perfect mechanics to where I never feel bad, and I think I just realized that that’s not real,” Glasnow said. “From the first game, it was something that I changed that I had never really done before. Just like no matter what I feel, just be athletic.”

New pitch mix

Going after hitters is one thing, but the Rays also seem to have identified Glasnow as part of the growing breed of dominant pitchers in today’s game: Ones who mix hard fastballs at the top of the zone with curves below it. Glasnow doesn’t have the natural four-seam spin that helps aces like Justin Verlander and Gerrit Cole make a living off high heat, but he can be just as overwhelming up there with his velocity and extension. Rays pitchers tied for the second-highest average pitch height on four-seamers last year, while the Pirates tied for 17th. The approach seems like it’s rubbed off on Glasnow in 2019.

Glasnow’s 4-seam fastball height and results, 2016-18 vs. 2019

2016-18: 2.55-foot avg. pitch height | .252 BAA | .429 SLG | 7.1% pop-up rate
2019: 2.85-foot avg. | .197 BAA | .342 SLG | 11.3% pop-up rate

Another point of emphasis for Glasnow is controlling his fastball’s direction. Again, he doesn’t possess the spin efficiency of a Verlander or Cole; those two are able to keep their fingers behind the baseball to give their heaters that "rising" effect (or, in reality, an ability to stay on plane and carry through the zone longer). Glasnow’s four-seamer has acted more like a cutter in his career, especially when he locates to his glove side:

But Glasnow is also working to add more carry to his four-seamer, as he detailed to FanGraphs’ David Laurila earlier this week. When he’s executed that carry, he’s been able to unleash a hellish heater that climbs up the zone. The Red Sox saw a couple examples of that during Glasnow's latest quality start.

If Glasnow can throw both types of fastballs consistently -- one with biting movement to the glove side, the other like an elevator ball on the arm side -- good luck to AL hitters. That sounds like the kind of fastball skill set Red Sox righty (and former Ray) Nathan Eovaldi dominated with last October.

And as tantalizing as that fastball profile is, it’s worth adding that Glasnow is throwing more curveballs than the past two seasons to keep hitters even further off balance. Opponents have struck out in nearly 44% of plate appearances ending on Glasnow’s hook, probably because they’re preparing for heat before Glasnow’s bender snaps to the dirt.

It appears the Rays had a plan when they traded Archer away last July -- no small gamble considering what Archer’s achieved in his career. While Archer can still be the ace that Pittsburgh envisioned when it shook hands with Tampa Bay, the Rays got a cheaper pitcher with more long-term control (not to mention Meadows, who owns a 1.097 OPS through 20 games). At this point, we shouldn’t be shocked at the Rays squeezing every bit of value out of their roster. But Glasnow is making them look smarter with every start.