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Development is not linear, and the Seattle Mariners are learning that the hard way with top outfield prospect Jarred Kelenic. The Mariners have demoted Kelenic, who is currently in an 0-for-39 slump, back to Triple-A, the team announced Monday. Infielder Shed Long Jr. was activated off the injured list in a corresponding move.

Kelenic, 21 next month, came into the season as one of the top prospects in the baseball. Our R.J. Anderson ranked him the No. 3 prospect in the game, calling him an "advanced hitter who should contribute across the triple-slash categories." Kelenic showed those skills in his second MLB game, when he went 3 for 4 with two doubles and a home run.

In the 21 games since though, Kelenic is 5 for 75 (.067) with one home run and 24 strikeouts. That includes his current 0-for-39 slump, which dates back to May 25. Here's what Mariners manager Scott Servais told reporters, including Bob Condotta of the Seattle Times, over the weekend:

"He certainly is struggling right now," Servais said. "He is putting a little bit of pressure on himself, like all guys do when they struggle. It's no different than anybody else. And that's young guys. That's for guys that have a couple of years in the league or are veteran guys. So, you know, we'll evaluate it day-to-day like we did everybody else. But he did a heck of a job in center field (Friday night). You know, he made a couple of outstanding plays. He's a good baseball player. He's just not getting a whole lot of hits, and a lot of luck."  

The Mariners sent Kelenic to the alternate site to begin the season in an obvious case of service-time manipulation. Former president Kevin Mather admitted as much earlier this year, when he said Kelenic rejected a long-term contract, and would spent a month in the minors this year. That's long enough to delay Kelenic's free agency, and that's exactly what happened.

Of course, Kelenic has proven to not be MLB ready to date, and sending him down is justifiable. He did tear up spring training though (.300/.440/.700), and it's fair to wonder whether spending a month at the alternate site slowed his development. The Triple-A season did not begin until May 6, and Kelenic went 10 for 27 (.370) with two homers in six games before being called up.

It's unclear how long the Mariners plan to keep Kelenic in Triple-A, and it is likely his performance will dictate when he returns to the big leagues. Sometimes great prospects need time to find their way -- Mike Trout hit .220/.281/.390 in 40 games in 2011, remember -- and Kelenic will get another opportunity with Seattle soon enough.

Former Marlins president David Samson weighed in on Kelenic's demotion on Tuesday's Nothing Personal with David Samson. Listen below:

At 30-31, the Mariners are in third place in the AL West, five games behind the first-place A's coming into Monday. They'll go with Mitch Haniger, Taylor Trammell, and some combination of Jake Fraley and Donovan Walton in the outfield in the interim.

In 2019, the last minor-league season, Kelenic authored a .291/.364/.540 batting line with 31 doubles and 23 home runs at three levels.