It has become the most elusive, and thus most coveted, trait in baseball: Raw power. Brute strength. The kind produced by fiercely swung bats, not from the seemingly endless supply of power arms these days capable of lighting up the radar gun in the high 90-mph range.

The Mariners, for the second consecutive year, seized the opportunity to add a highly regarded right-handed power hitter with their top pick in the draft. Alex Jackson was a catcher from the storied program at Rancho Bernardo High School in Escondido, Calif., and he will start out as a right fielder with the Mariners. But as area scout Gary Patchett put it: “He’s a hitter. The ball makes a different sound off his bat.”

As Mariners fans know all too well, the road from the exhilaration of draft day to actual production in the major leagues can hit detours and dead ends. But with corner infielder D.J. Peterson, last year’s top choice (No. 12 overall) tearing it up in the minors, and now Jackson, the Mariners might have the right players to soon end a glaring and ongoing deficiency.

Then, for added measure, the Mariners took another right-handed power prospect with their second and final pick of the draft’s first day, No. 74 overall: 6-foot-4, 220-pound outfielder Gareth Morgan from Toronto, whose power is rated as a 70 on the 80-maximum scouting scale.

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Ask general manager Jack Zduriencik about the industrywide dearth of power hitters, and he says wryly: “Yeah, you’ve noticed. It’s difficult. It really is. Especially a right-handed bat. We’ve talked about that a lot. We’re talking about it now. It’s funny, I remember years ago it was left-handed bats, trying to find a really good left-handed hitter. Now it just seems it’s the right-handed bat that’s at a premium.

“The game’s changed a little bit, and you look at this kid that’s been playing in all these showcases for several years. He’s traveled all over the country, been in every major event possible, comes from a great high-school program. This was intriguing to us, and we’re very happy to select this player.”

Patchett, who is based in Southern California, spent vast amounts of time in the San Diego area watching not only Jackson, but left-handed pitcher Brady Aiken, who went No. 1 overall to the Astros. Aiken and Jackson, friends and travel-ball teammates, faced each other just once, in a preseason scrimmage that was like a carnival for scouts. For the record, Aiken struck out Jackson looking on a pitch Patchett described as (and YouTube video confirmed to be) “borderline.” But one at-bat isn’t what defines the 6-foot-2, 215-pound Jackson. It’s that ever-enticing mixture of performance (he hit 47 homers in high school, tying the San Diego section record) and potential that made him Baseball America’s top-ranked position player.

“Alex is an unbelievable talent,” Patchett said. “He has a ton of bat speed. He can definitely do special things in the batter’s box.”

The first time Mariners scouting director Tom McNamara saw Jackson play in a game, Jackson fell a single short of a cycle.

“The most impressive thing was he hit the ball to all fields,” recalled Patchett. “There was a ground-rule double to right, a homer to dead center, and a triple to the left-center field gap. One thing with Alex — every time you saw him, he did something better each time.”

Part of the fun of draft day, of course, is hauling out the comparables for the new player — and the more exalted, the better. For instance, some have related Jackson’s expected move from catcher to outfield to Bryce Harper, others to Wil Myers. Heck, even Zduriencik plays the game.

“That’s something I always ask the guys, who do you compare him to?” Zduriencik said. “There were a lot of nice names that came up. I go back to the Area Code Games in California, and some of the best players ever came out of there; our scouts had comparisons with several players.

“You don’t put a label on guys, but there are similarities to a lot of pretty good young hitters that were advanced for high-school kids.”

As with most dominant high-school kids, the evaluation process can be tricky because opponents tend to pitch around them. But even that inconvenience merely enhanced the Mariners’ perception of Jackson.

“He’s one of those guys, he might go 1 for 1 with three walks. Or 0 for 1, just missing a ball, and walk three times,’’ Patchett said. “I never saw it get to him from a frustration standpoint. He took his walks, and never expanded his zone or changed what he’s trying to do.”

Above all else, Jackson is a hitter who can drive the ball to gaps and over walls.

Much of what was said about him was said last year about Peterson, who hit at Everett (.312 with six homers in 29 games before a broken jaw ended his season) after signing; and is hitting so well right now at Class A High Desert (.313, 11 homers, 51 runs batted in) that a promotion might be imminent.

These days, that type of raw power is a rare and precious commodity, one that left the Mariners feeling ecstatic when Jackson fell to them Thursday.

“Especially in college and high school, with the bats they’re using now, the balls don’t really fly,’’ Patchett said. “When you see a guy who really moves the baseball with those bats, you know there’s something there. We’ve seen Alex use wood bats, and he puts on a show with wood as well.”

It’s a show the Mariners can’t wait to see.