SEATTLE -- After seeing most of his team’s young nucleus take a solid step forward this season, Mariners general manager Jerry Dipoto believes the club is on schedule to make a strong push for the playoffs in 2021.

Speaking on a postseason video call with the media on Monday, Dipoto said his biggest offseason focus will be improving the bullpen as the Mariners look to continue putting the pieces together on a team that surprised many by finishing third in the American League West at 27-33 and went 20-15 to close the shortened season.

Dipoto expects Mitch Haniger to be the Opening Day right fielder after being sidelined the past 17 months by several surgeries to his core and lower back. The GM also believes next year’s club will be further bolstered by the additions of such top prospects as Jarred Kelenic, Logan Gilbert and Cal Raleigh at some point during the season.

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The club could add a veteran starter to strengthen what is expected to be a six-man rotation, but for the most part, the youthful core that began falling into place this past year will remain the nucleus going forward.

Dipoto said the biggest uncertainty is what the lack of a Minor League season did for the younger prospects, though that group will benefit some by a 20-game slate of instructional league action in Arizona this fall.

“The next wave of players, I’m not entirely sure what the timing looks like or their progression, but I know with the group that will come back and what we anticipate adding to our club via free agency or trade, I think we’re in a really nice position for 2021,” Dipoto said. “Our goal will be to go out there and contend for a playoff spot. And I don’t think that’s an unrealistic goal.”

Dipoto has built a reputation as the most active general manager in baseball, having worked frenetically at times trading and turning over the roster in his five years in Seattle. But that churn slowed last year once the younger nucleus was in place. Now Dipoto has a narrow focus on this offseason’s pursuits.

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The Mariners will have some payroll flexibility. With Dee Strange-Gordon’s $14 million team option for 2021 not expected to be picked up, the only high-priced veterans will be Kyle Seager ($18 million) and Yusei Kikuchi ($15 million). The next-highest-paid player is No. 1 starting pitcher Marco Gonzales at $5 million, and the vast majority of the roster consists of players earning around the $575,000 minimum, still in the service-time range of 0-3 years

Dipoto didn’t rule out taking a “big swing” in free agency, but the Mariners are relatively set with younger players at most positions.

“For me,” Dipoto said, “the focus this year going into the offseason, we’re looking at the bullpen and I’d like to add three or four guys down there that can stabilize that group and give us some certainty as we move toward the end of a game.

“There’ll be guys that have experience in the league that we feel can help us moving forward. I don’t know that they’ll be marquee names. That’s not generally how bullpens work. But that’s where we’re most focused in trying to help the ’21 team improve.

“Along the way, if there’s opportunity, we’re definitely going to have our ear to it. We’ve created flexibility on our roster and within our payroll. If we have the opportunity to make a difference and it makes sense for us, then we’ll look at it.”

Make no mistake, the Mariners’ primary plan is to let their youth continue to develop, as they did this season with center fielder Kyle Lewis, first baseman Evan White, shortstop J.P. Crawford, starting pitcher Justus Sheffield and others. There are more promising prospects waiting to bolster that group, and it would make no sense to block their progress with veteran free agents, in most cases.

“A lot will depend how quickly the next wave adapts, like this first set of guys did,” Dipoto said. “I can’t say enough about Sheff and Kyle Lewis and the way we started to see Evan adjust and Dylan Moore’s breakout.

“That really puts us in a great situation if Logan Gilbert and Cal Raleigh and Taylor Trammell and Jarred Kelenic have that same type of transition. Then next year we could be really fun to watch, and there’s no doubt in my mind that we could be in the mix.”