There are seven players in the major leagues this season who are least 40 years old. A few are taking the final steps on a path to the Hall of Fame, and others are trying to wring one more year out of the only profession they’ve ever known.

But only two are on the same roster: David Ortiz and Koji Uehara of the Red Sox.

For manager John Farrell and the team’s medical staff, it’s no nostalgia act. Ortiz is the best hitter in what has been the most productive offense in the game, and Uehara has been a valuable late-inning reliever.

Their ability to stay on the field over the final 3½ months of the season could determine whether the Red Sox return to the postseason.

“These are very important players for us,’’ Farrell said. “I mean, what David is doing is unprecedented.’’

Ortiz, who turned 40 last November, revels in his elder statesman status, dispensing advice to teammates and making frequent, generally unprintable jokes about the ravages of age. Ortiz announced his retirement before the season and is clearly enjoying the closing act of his career.

It has led to Ortiz being the best offensive player in the game. He is hitting .338 with a 1.153 OPS, 26 doubles, 16 home runs, and 55 RBIs over 53 games.

“He’s having one of his best seasons, maybe the best,’’ said Dustin Pedroia, who has played the longest with Ortiz. “It’s fun because we’re winning but it’s also because you’re seeing how much it means to him.’’

It’s less joyous for Uehara, who hit 41 in April and tries to avoid the topic of age and when he will throw his last competitive pitch.

“I don’t think about my age unless I get asked about it,’’ he said, casting a disapproving glance at his interrogator. “I don’t judge myself on age. It’s how I perform.’’

Uehara has no plans to retire. His contract with the Red Sox expires after the season but he hopes to stay in the majors for another season or two, whether it’s in Boston or somewhere else.

“I’ll pitch until nobody wants me,’’ he said via translator C.J. Matsumoto. “Papi is going home but I’m not ready yet.’’

Uehara looks to the examples set by former Yomiuri Giants teammates Masumi Kuwata and Kimiyasu Kudo.

Kuwata pitched 20 seasons for the Giants, winning 173 games and numerous awards before appearing in 19 games for the Pittsburgh Pirates in 2007. Kudo played for an incredible 29 seasons, pitching until he was 47.

“I watched what they did and learned all I could,’’ said Uehara, who has appeared in 24 games this season and has a 4.37 earned run average. “My goal then was to pitch as long as I could and it still is.’’

Special considerations

It’s always Old Timers’ Day for Farrell, who has to weigh the value of one game against making sure two of the oldest players in the game are properly rested and can stay productive.

Farrell and Ortiz talked in spring training about the importance of days off during the season regardless of pitching matchups or whether Ortiz was swinging the bat well at the time.

In four interleague road games so far this season, Ortiz has been used only as a pinch hitter — and not as a first baseman — in an effort to protect his legs.

Farrell also has paired up days off for Ortiz with scheduled days off for the team to give him a 48-hour break. Travel is another consideration.

“You trust that they have a good feel for what their body needs,’’ Farrell said. “With David, you need that communication because you want him in the lineup every day but you know that’s not possible.’’

That Farrell and Ortiz have built up trust going back to the manager’s tenure as the team’s pitching coach from 2007-10 makes the process less complicated than it can be for other managers dealing with older players.

“What I typically do is go to David and say, ‘This is what we have coming up, pick a day,’ ’’ Farrell said. “It’s not so much who we’re facing. It’s what’s best for him. He’s been good about it.’’

Ortiz gave up fighting to stay in the lineup a few years ago.

“I thought when I was 20 I would feel the same way when I was 30 or 40,’’ he said. “It doesn’t work that way. You need to take care of yourself. One day off helps me for three or four days.’’

For Uehara, it’s a matter of pitches. The Red Sox chart how many he throws over a 10-day period, and when the limit is reached, Farrell backs off for a few days.

There are other Koji Rules, too. If Uehara warms up, he gets into the game unless there are unusual circumstances. For a pitcher his age, warming up to pitch is essentially the same as coming into the game.

The Sox also try to avoid using Uehara in day games. Since the start of the 2014 season, Uehara has a 2.33 earned run average in night games and 3.76 during the day — 9.00 the last two seasons.

“I need my sleep,’’ Uehara said. “For me, that’s important. But I should do better in day games. Maybe I really am too old.’’

Support staff

Farrell makes most of his decisions after consulting with the medical staff. The Sox travel with three athletic trainers, two strength and conditioning coaches, two massage therapists, and a physical therapist.

At home, that group expands to include team doctors Larry Ronan and Peter Asnis, and Dan Dyrek, the organization’s director of sports medicine services and a nationally respected physical therapist.

“You take away those guys and I’m home,’’ Ortiz said. “Simple as that. The last five years, you see more and more of the medical people around teams. We have a good group.’’

Head athletic trainer Brad Pearson, 38, is in the unusual position of administering to two players who are older than he is. He has been with the Red Sox for 14 years and worked with many of the major league players since they were prospects.

“It’s a big brother type of relationship with those guys,’’ he said. “But not with David and Koji. They’re unique.’’

For Ortiz, the easiest part of his day is when the game starts. For a typical night game, he arrives at the park at noon and undergoes treatment on both of his Achilles’ tendons and his right calf.

If good hitting starts from the bottom up, Ortiz is on a crumbling foundation. The cumulative wear on his legs is a big part of what led him to make this his last season.

“You can see when he runs, he’s not exactly gliding,’’ Farrell said.

Getting ready for the season also became more of a chore. The weightlifting and conditioning work Ortiz once enjoyed has become a hardship in recent winters.

“I do the same things now I did when I was 22,’’ he said. “It’s just harder to do. The first couple of weeks, I was throwing up. You sit there and you’re like, ‘Why am I still doing this?’ ’’

Uehara typically arrives five hours before first pitch, earlier if he plans to lift weights.

“I have to get ready body-wise much more than I used to during the season,’’ he said. “I start much earlier in the offseason, too, usually in the middle of October.’’

Said Farrell: “You can’t take away the guy’s work ethic. When you see him in here after games, the way he works out, it’s a testament to his ability to keep himself in great shape.’’

Uehara has some other advantages. He did not pitch often as a school player in Japan, which saved his arm from the high pitch counts that are considered normal in that country.

“That’s something in conversation, getting to know Koji, that possibly his physical development was able to take place before the stress of pitching continuously as might be the case with other Japanese pitchers,’’ Farrell said.

Ortiz and Uehara haven’t had many long discussions about their longevity. For now, it’s a time to enjoy still being able to play.

“I know he feels the way I do — you never expect to play this long,’’ Ortiz said. “Every day I come to the clubhouse, it’s a good day.’’

ACTIVE MAJOR LEAGUERS AGE 40 OR OLDER

RHP Bartolo Colon (Mets) 43

OF Ichiro Suzuki (Marlins) 42

RHP Koji Uehara (Red Sox) 41

RHP R.A. Dickey (Blue Jays) 41

DH Alex Rodriguez (Yankees) 40

DH David Ortiz (Red Sox) 40

RHP Joel Peralta (Mariners) 40

? Red Sox draft LHP Groome 12th overall. D7

Peter Abraham can be reached at pabraham@globe.com. Follow him on Twitter @PeteAbe.