Jarred Kelenic, Mariners scouting report

Former Seattle Mariners CEO Kevin Mather suggesting his team manipulated the service time of prospect Jarred Kelenic confirmed what the MLBPA long believed. Clubs intentionally exploit the service time of young players to delay arbitration and free agent eligibility. Even projected stars fall victim to this practice.

“Because there was no chance you were going to see these young players at T-Mobile Park. We weren’t going to put them on the 40-man roster. We weren’t going to start the service time clock.” – Kevin Mather

Mather’s revelation will undoubtedly have ramifications during CBA negotiations between MLB and the MLBPA later this year. The relationship between both parties was already acrimonious. Mather’s unprovoked admission to an unethical practice only worsens matters, assuming that’s possible.

So what about Kelenic? Should the Mariners avoid further negative publicity by promoting him to their Opening Day roster? That depends on the answer to one question.

Is he ready?

To be honest, I have no idea whether Kelenic is ready for the majors. Nobody outside the Mariners does. Several national media members have advocated his readiness, while passionate fans have taken to Twitter doing the same. Still, most of these folks haven’t seen Kelenic play in a regular season game nor could they pick him out of a lineup.

Instead of engaging in hyperbole about Kelenic’s current plight or connecting it to the Mariners’ 20-year absence from the postseason, let’s try something else. Have a rationale conversation based on recent history, available facts, and objective opinions. Maybe then, we can arrive at a conclusion regarding the sixth overall pick of the 2018 draft.

History Lesson

Although Mather’s comment about the service time of his former team’s minor leaguers was egregious, the MLB readiness of those players is debatable. That wasn’t the case with two prominent players, who seemingly had their service time manipulated in the last six years.

In 2015, the Cubs started Kris Bryant in the minors after he led all of professional baseball (including MLB) with 43 home runs and a 192 wRC+ the year prior. Chicago promoted Bryant twelve days later guaranteeing an additional year of service from the 2015 NL Rookie of the Year. Bryant later filed a grievance against the Cubs over the perceived service time manipulation, but lost in judgement.

Weighted Runs Created Plus (wRC+) quantities how a hitter’s total offensive value compares with the league average after adjusting for park effects. Every point above 100 represents a percentage point above average. League-average is always 100.

The Blue Jays executed a similar maneuver with Vladimir Guerrero Jr., who had the highest AVG, SLG, and wRC+ among minor leaguers with 400-plus plate appearances in 2018. Despite his success, Toronto opted to leave Guerrero in the minors at the beginning of 2019 before recalling him a month into the season. The tactic assured another season of club control for the Jays.

There are other instances of seemingly unethical service time decisions. However, the Bryant and Guerrero sagas are two of the most glaring examples of why players are fighting mad with ownership. Mather’s comments simply raised the temperature in an already simmering pressure cooker.


Let’s review Kelenic’s offensive numbers from his last season in 2019. The left-handed hitter played with three teams – Class-A West Virginia, High-A Modesto, and Class-AA Arkansas. The following illustrates his combined production and its ranking against 686 players from all levels with 500-plus plate appearances. Also included, Kelenic’s standing among the 107 individuals under age-21.

How Jarred Kelenic Ranked vs Other MiLB Players (2019)

Overall, Kelenic’s numbers look great, particularly against youthful peers. After joining Arkansas on August 11, he slashed .253/.315/.542 with six home runs. Furthermore, his .857 OPS was higher than the output of other top Seattle prospects when the Wisconsinite was their teammate. Specifically, major leaguers Kyle Lewis (.526) and Evan White (.789), plus catcher Cal Raleigh (.761).

Kelenic’s 133 wRC+ with Arkansas ranked fourth on the team for the season behind leader Jake Fraley (156). Fraley left the Travelers to play with Class-AAA Tacoma and then the Mariners in 2019. His situation is why minor-league stats don’t have much relevance to me.

Despite the success in MiLB, Fraley has yet to establish himself in the majors. The 25-year-old has a .152/.200/.227 slash-line with a 16 wRC+ in 70 MLB plate appearances in 2019-20. To be fair, an injury derailed his first year shortly after he debuted and opportunities have been rare ever since. It’s also worth pointing out Lewis was slumping before his September call-up in 2019. He then took Seattle by storm with six home runs in 18 games.

Honestly, the most relevant number to me is Kelenic’s playing time, which is very limited above Class-A level. His stint with Arkansas totaled 21 games with 83 plate appearances. Few players from this generation have reached the majors with less MiLB experience and at similar young age.


With this in mind, let’s contrast Kelenic’s MiLB career to other players recently debuting at an early age. How many spent more time in the minors than what the Waukesha West High School product currently has?

The following illustrates all MiLB games played and at AAA/AA by 14 hitters debuting by their age-20 season since 2010. Two caveats; they had to play 40-plus games during their debut campaign and produce at least a 0.0 bWAR. We’ve sorted our list by games played at AAA/AA. Kelenic is included to aid with our comparison.

MiLB Total & AA/AAA Games Before MLB Debut
Ozzie Albies
Giancarlo Stanton
Ronald Acuña Jr.
Manny Machado
Fernando Tatís Jr.
Vladimir Guerrero Jr.
Rougned Odor
Rafael Devers
Mike Trout
Carlos Correa
Bryce Harper
Starlin Castro
Jason Heyward
Jarred Kelenic
Juan Soto

As you can see, our list is teeming with recognizable names. Only two players – Bryce Harper and Juan Soto – debuted with less than 200 MiLB games. It’s worth noting both began with the Nationals and have been successes ever since. Harper won 2012 NL Rookie of the Year. Meanwhile, Soto has been so electric Mike Petriello of MLB.com recently drew a comparison between the 22-year-old and Hall of Famer Ted Williams.

Based on Kelenic’s inexperience in the minors, it’s understandable why Mariners GM Jerry Dipoto insists his team hasn’t delayed his star prospect’s march to the majors. That doesn’t mean there wasn’t any monkey business going on behind the scenes. However, there’s a plausible explanation, based on precedent, as to why Kelenic has yet to join the big-league team.


Okay, we’ve compared Kelenic’s stats to peers and his MiLB experience to major leaguers debuting at a young age. Let’s now consider how four national outlets recently evaluated his future. The following are only snippets from their write-ups. All ranked Kelenic fifth or better on their top-100 list.

He probably would have debuted in 2020 had there been a full minor-league season, and I expect he’ll be up by the middle of 2021. I know it pains Mets fans to read this, but I think Kelenic is going to be a superstar. – Keith Law, The Athletic

I expect him to come up in 2021 and be an immediate impact player. – Eric Longenhagen, FanGraphs

Kelenic has an all-star potential and his major league debut is on the horizon in 2021. – Bill Mitchell, Baseball America

Kelenic performed well in a 21-game Double-A sample in 2019. He first stood out on the national stage after his sophomore year in high school, so he has a long track record of standout offensive performances that gives scouts some certainty that it will continue. – Kiley McDaniel, ESPN

Obviously, these are subjective anecdotes. That’s how readers likely view them. My takeaway is all four assessors agree that Kelenic projects to debut in MLB this year. However, none states he’s ready to begin the season with the Mariners. Then again, they may avoid such language when discussing prospects.

On the subject of evaluations, Prospect Insider’s Jason A. Churchill is in the process of publishing his annual top Mariners prospect reports. Numbers 1-3 release on February 26-28. Spoiler alert: Kelenic’s name has yet to appear. You can click on Jason’s name to find previously published reports, including his most recent offering – number-3 prospect Emerson Hancock.

Editor’s note: Kelenic’s report by Churchill has since published and can be found here.


Does Kelenic need more seasoning in the minors or should the Mariners play him on Opening Day? Even after our discussion, I still don’t know the answer. His production was excellent, but not the best in MiLB as was the case with Bryant and Guerrero. Moreover, both of those players spent time at AAA – Kelenic has not.

I don’t see how anyone could rationally determine whether Kelenic should be on the Opening Day roster without personally evaluating him. For this reason, I’ll continue placing my faith in the assessments of Dipoto and his staff.

I realize many of you won’t agree and that’s fine. However, Dipoto has been extremely transparent about baseball operations since his arrival in late 2015. More so than any GM in MLB and perhaps all major sports. Besides, he didn’t hesitate to recall top prospects Lewis and Justin Dunn in September 2019. Why? He and his staff deemed both ready to test the waters in the majors.

Sure, Mather’s buffoonery gives us pause regarding the way the Mariners run their business and the organization’s culture. Still, we should separate the two issues at hand. Whether Kelenic is actually ready in the eyes of professional evaluators has nothing to do with Mather telling fans his former team was conspiring to manipulate the service time of its best prospects.

As for the latter issue, Mather has resigned. Now, Mariners Chairman and Managing Partner John Stanton has the daunting task of repairing the serious damage done to his franchise’s reputation by his former CEO. I don’t envy Mr. Stanton.

Regarding player personnel decisions, Stanton remains comfortable with Dipoto making the call on when to promote prospects – so do I. The sixth-year GM reinvigorated a farm system once considered the worst in MLB. Now, the Mariners’ system is both deep and full of top-100 prospects. They seem to have a handle on developing minor leaguers.

Besides, I have no idea when Jarred Kelenic – or any prospect – deserves a promotion to the majors.

And neither do you.

My Oh My…

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Last Updated on March 27, 2021 by Luke Arkins

Image courtesy of Darron Cummings / AP Images
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Luke Arkins

Luke is a native New Yorker, who grew up as a Mets fan. After the US Navy moved him to the Pacific Northwest in 2009, he decided to make Seattle his home. In 2014, Luke joined the Prospect Insider team. During baseball season, he can often be found observing the local team at T-Mobile Park. You can follow Luke on Twitter @luke_arkins