WASHINGTON -- An examination on Thursday revealed that Wilmer Flores is dealing with early-onset arthritis in both knees. Flores, 27, is done for the season, though he remains optimistic about his future prognosis.
"Hopefully, it's not something I have to deal with my whole career," Flores said. "I'm going to do everything I can to keep the pain away."
It was a disappointing campaign for Flores, who amassed his highest plate appearance total since 2015 but hit just 11 homers, his lowest number in four years. Overall, Flores batted .267 with a .319 on-base percentage and a .417 slugging mark. One of the game's most potent weapons against left-handed pitchers from 2015-17, Flores hit just .237/.284/.326 against them this summer.
Now, his season is over, though the Mets believe he will be fine long before the start of Spring Training. Doctors gave Flores a hyaluronic acid injection, a common treatment for osteoarthritis, and told him he should be pain-free in about a month.
"It's not like surgery is recommended at this time or anything," manager Mickey Callaway said. "Rest and a couple of injections is supposed to knock this out pretty good."

Although most types of arthritis are not curable, they can be managed with proper treatment. In particular, Flores said, he will need to do more lower-body work to keep his quadriceps strong, thereby keeping pressure off his knees.
"I don't think it's really going to affect me," said Flores, noting that he had been experiencing knee pain for about six weeks before committing to treatment. "I just had to take care of this right away because it was going on for a while. I was just trying to stay out there playing, but at this point in the season, I didn't see any reason. My decision was to start taking care of this."
The issue complicates the Mets' offseason assessment of Flores, who is under team control for one more season, and due an arbitration raise from the $3.4 million he made last year. Although Flores started a team-high 73 games at first base for the Mets this season, the club expects to give reps at the position to Jay Bruce, Dominic Smith and No. 2 prospect Peter Alonso in 2019.
When asked about Flores' future role, Callaway demurred.
"That's really hard to say," the manager said. "I think that really depends on what the rest of our team looks like. He can definitely obviously fill in, and start, and swing the bat well and play good enough defense. … We'll just have to see what the makeup of our team looks like next year."