SEATTLE -- An injury-plagued season for Mitch Haniger came to an end Sunday, but the 28-year-old outfielder remains a big part of the Mariners’ future plans, and he expects to be fully healthy and back to training for next year in another month or so.

Haniger missed the final four months of the season after fouling a ball off himself and rupturing a testicle on June 6, then dealing with issues from that surgery after pushing too quickly to return. He spent the past two months sidelined by back pain that he believes is related to that recovery, but he is finally seeing daylight at the end of the tunnel.

“It’s doing good,” Haniger said before Sunday’s season finale against the A’s. “I’m just kind of building up everything. It’s been going well the past week. There have been a lot of ups and downs, but I feel I’ve been making steady progress for probably a week and a half now.”

Haniger will spend the next two weeks in Seattle with the Mariners' training staff, then head to his offseason home in California to continue rehabbing.

His immediate future?

“Get stronger, do some therapy,” Haniger said. “It shouldn’t be long before I’m sprinting and hitting and throwing.”

Mariners general manager Jerry Dipoto said Haniger's recovery will be closely monitored as plans are put together for next year.

"His offseason is going to be pretty critical to our understanding of where he is," Dipoto said. "But we expect that he can be 100 percent healthy when we take the field in the spring, and I know that 100 percent of Mitch Haniger is probably our best player. We're looking forward to seeing what he looks like when he gets out there."

Haniger said he typically scales back during October anyway before starting to again focus on baseball preparation in November.

“It’ll be a little different, because I’ll have a little limitation this next month,” Haniger said. “But for me, October in the past has been mostly weightlifting and working out for fun and then, when November starts, it’s baseball specific. This will be a little different, but I don’t think it’ll mess with my timeline as for when I can start doing everything. So it should be OK.”

After an All-Star season in 2018, Haniger struggled offensively in the first two months this year, batting .220/.314/.463, though he had 15 homers and 32 RBIs in 63 games. Though things didn’t play out the way he hoped, Haniger said the season reinforced some important things both for him and his young teammates.

“It’s been a learning experience,” Haniger said. “It’s been frustrating in a lot of ways, but it’s been good for me to go through something like this. Just for the clubhouse and everyone to make sure winning is a priority. I think it’s really hard to have fun when you lose a lot. For me, winning is really fun and losing is not.

“So it’s been a little bit of a grind, but I think we’re going to come out better from this season and look forward to next year and moving forward.”

Haniger is still viewed by the Mariners as one of their core players in the rebuilding process, and he’s been intrigued by their youthful additions.

“It’s been exciting to get some young guys in here who are hungry,” Haniger said. “I think next year, their goal should be the same as everyone else’s, just get better in the offseason and keep putting the work in, not getting complacent, thinking you’re going to have a job here next year.

“No matter how many years of service time you have, that needs to be your mindset. To come in better the next year than you left and be ready to go, because there are hundreds of guys coming for our jobs every day.”