Seattle Mariners manager Scott Servais spent parts of 11 seasons and nearly 800 games behind home plate as a catcher with four franchises, mostly in the 1990s.

During that era 鈥� one dominated by Hall of Famers Mike Piazza and Ivan Rodriguez 鈥� the skills needed at backstop were clearly defined.

鈥淐ould you throw guys out, how did you do blocking the ball and could you hit with power?鈥� Servais said. 鈥淭hat鈥檚 how the position was evaluated.鈥�

A generation later, those attributes have been joined by a more subtle but equally significant skill: pitch framing. During baseball鈥檚 data revolution, the fine art of making borderline pitches look like strikes was found to be a game-changing craft 鈥� one that could be as impactful as Piazza鈥檚 power or Rodriguez鈥檚 arm.

The calculus, though, could be about to change, along with an equation that鈥檚 included the human element for nearly 150 years.

While , and other debut this year at the major league level, the Automated Ball-Strike System will receive its biggest experiment yet at Triple-A. ABS will be used four days per week to call every pitch at baseball鈥檚 highest minor league level. On the other three days, umpires will traditionally call balls and strikes with a challenge system in place 鈥� teams will be able to appeal a handful of calls to the so-called robo-zone each game.

To many, ABS has begun to feel inevitable. to allow it at the major league level when it is ready. Which means that within a season or two, everything around home plate could change.

鈥淚t鈥檚 going to be here,鈥� Servais said.

Others think Major League Baseball, and specifically Commissioner Rob Manfred, don鈥檛 recognize how seismically such a shift could alter the sport.

鈥淚 don鈥檛 see it happening,鈥� said Yankees All-Star and distinguished pitch-framer Jose Trevino. 鈥淚 don鈥檛 think Manfred has any idea what鈥檚 going on whenever he talks about that kind of stuff. He鈥檚 obviously never put the gear on, so he doesn鈥檛 know.鈥�

Manfred, who last summer told ESPN that ABS could reach the majors by 2024, has cautioned this spring that the robo-umps remain in 鈥渢he evaluation phase.鈥� In order to be adopted in the big leagues, ABS would need to be approved by an 11-member competition committee that includes four players.

鈥淭here are issues that are still the topic of really considerable discussion within the ownership group and even more that are going to have to be resolved in the joint committee process with the players,鈥� Manfred said. 鈥淭he framing issue is one of those. I mean it鈥檚 a legitimate concern on the part of at least a subset of players.鈥�

The subset includes some coaches, too, including New York Yankees director of catching Tanner Swanson 鈥� a pioneer of sorts in teaching backstops to steal strikes.

An appreciation for pitch framing had been under way for nearly a decade when Swanson jumped from college coaching to join the Minnesota Twins organization before the start of the 2018 season.

Among his most impactful ideas: If catchers received pitches while down on one knee as opposed to a traditional squat, they鈥檇 be better positioned to steal strikes near the bottom of the zone. Within just a couple seasons, the one-knee approach he coached with Minnesota was being used across the majors.

鈥淲hen I got into pro ball, I think it really kind of opened the curtain to like, 鈥極K, now this is not only extremely valuable, but this is something that we should be prioritizing just in terms of the frequency in which it happens relative to all the other skills.鈥欌�� Swanson said.

Swanson preaches subtle movements with the glove on every borderline pitch 鈥� just enough trickery to sway even the most well trained umpire. Even if it came at the expense of blocking pitches or throwing out runners, the data showed framing trumped all other skills.

Swanson has had several notable success, starting with Mitch Garver in Minnesota and most recently Trevino, who was an All-Star and Gold Glove winner last season. Trevino converted 53.8% of non-swinging strikes on the edges of the zone into strikes 鈥� best in the majors, according to MLB鈥檚 Statcast.

The knee-down catching technique is already being taught to youth catchers on up, and there鈥檚 now an entire generation of big league catchers trained to put pitch presentation first.

鈥淔raming鈥檚 always been big,鈥� said Baltimore catcher Adley Rutschman, last year鈥檚 AL Rookie of the Year runner-up. 鈥淪ince probably my junior year in high school, it鈥檚 been a big point of emphasis. Got to college, same thing, and in the pros, same thing.鈥�

Robot umpires, of course, can鈥檛 be fooled. So what happens when framing falls out of focus?

One name comes to mind for Servais: Piazza.

鈥淢ike was actually a pretty good receiver. But he could bang it, he could really hit and he just changed the position in my era,鈥� Servais said. 鈥淪o there鈥檒l be more emphasis put on offense.

鈥淩eceiving won鈥檛 matter at all. You鈥檒l see guys set up with guys on base in throwing position, their bodies will be halfway turned because it won鈥檛 matter. So you鈥檒l teach the position differently.鈥�

Unless, of course, receiving does still matter.

鈥淲hen you have two alternatives, some of those alternatives are better at addressing issues,鈥� Manfred said. 鈥淥bviously, the challenge one reduces dramatically the framing issue for catchers in terms of the value placed on framing. So you know, more to follow on that one, but I think it鈥檚 a mistake to automatically assume that ABS is coming on any particular timeframe.鈥�

Regardless, Swanson believes one-knee down stances are likely here to stay because it takes stress off catchers鈥� bodies and puts them in better position to block pitches, with their body already centered lower to the ground.

But the valuations and evaluations will change if framing鈥檚 significance is lessened.

鈥淚 don鈥檛 think it鈥檚 good for the game at all,鈥� Trevino said. 鈥淭here鈥檚 guys out here that are good defensive catchers for a real long time. Guys that are still in the game that are defensive catchers. I think that takes away from the art of the catcher.鈥�

鈥擳im Booth, The Associated Press