BOSTON — At the end of the on-field press conference to announce Dustin Pedroia's eight-year contract extension back in 2013, then-general manager Ben Cherington was asked why the organization believed Pedroia could perform deep into his 30s — unlike many second basemen.

"Sometimes there comes along someone who is a little bit different — and Dustin is different," Cherington said. "You have to layer on who he is — how he goes about his business, his work, how he prepares, how he plays the game and all those things. After doing all that work, we feel like, if we're going to bet on someone at 37 or 38 years old, we're not sure there's a better guy to bet on."

"I'll get you later," Pedroia joked with the reporter.

By that point, Pedroia had built a career playing through pain; the day that extension was signed, he was posting another excellent season despite playing through a torn ligament in his thumb. But four years later, now halfway through that long-term extension, the Red Sox and Pedroia face their most serious health question yet.

Pedroia has spent this week meeting with doctors and visiting specialists about the condition of his left knee. The second baseman underwent surgery on that knee last offseason, then aggravated it back in April on Manny Machado's hard slide into second. In the second half of the season, Pedroia spent two different stints on the disabled list with knee inflammation; he didn't play nine innings in the field on consecutive days between July 26 and the postseason.

On Monday, at the end of the season, Pedroia sounded an ominous bell with regard to his future outlook.

"Obviously, we had to try and find a way to do what we did so I could be out there," he said. "But if you were to get it fixed, the recovery is a long time. So I have a lot of things to weigh in with the doctors and figure it out."

"He has a bad knee that he's going to have to watch and we're going to have to watch for the rest of his career," president of baseball operations Dave Dombrowski memorably said back in July.

Pedroia seemed to set two possible courses of action: Continue on the way he played the final two months, or undergo surgery and miss some chunk of 2018.

It's hard to imagine the first option being all that viable. Despite spending all but one day in August on the DL, despite getting regular rest in September through late-game substitutions, days at DH and full games off, Pedroia still appeared a shell of himself at the plate and in the field.

Including the postseason, Pedroia hit .220 with a.301 on-base percentage and .280 slugging percentage after his return on September 1. Perhaps even more jarring was the occasional uncertainty he showed in the field on an unstable knee; there was a routine ground ball he essentially tackled in the ALDS.

His toughness notwithstanding, is that the Pedroia the Red Sox want to play for the next four seasons?

Of course, there's no guarantee surgery completely mends the problem; what one imagines was a less extensive procedure last winter clearly didn't. And if Pedroia is to go under the knife and be forced to miss some significant stretch of next season, Boston will have to prepare for that absence.

While there are plentiful in-house options to back up Pedroia, none should fill the Sox with confidence if forced into everyday action. Brock Holt was one of the worst players in the American League this past season, and he's had lingering and serious health concerns of his own the past two seasons. Marco Hernandez is coming off a lost season because of shoulder surgery. Deven Marrero and Tzu-Wei Lin are each one year removed from being two of the worst hitters in minor-league baseball.

That could mean the Sox aggressively try to bring back Eduardo Nuñez, though Nuñez should have his pick of everyday jobs rather than temp gigs. Boston could look for a stopgap solution like veteran free agent Brandon Phillips or trade for Oakland's Jed Lowrie.

Or maybe it's time to consider a longer-term replacement for Pedroia, though who that would be is unclear. Pedroia's contract never becomes onerous in terms of dollars; even this past season, he was worth his $15 million salary.

But the Red Sox were fortunate that the homestretch of David Ortiz's career never became awkward, because the slugger never declined. Boston didn't have to worry about delicately reducing expectations and/or playing time, or moving Ortiz down in the order.

Whichever path Pedroia and the Red Sox take in the coming weeks, this feels like a pivot point in the second baseman's career — the moment when he moved from being a centerpiece to a complement, when the decline phase for a player now into his mid-30s started in earnest.

"There's no secret. I don't think anybody has a secret on how to play any position," Pedroia said years ago, when asked about maintaining his performance into his 30s. "My job is to show up to win every day. If I do that, I do my job. I don't think about the other things."

The Red Sox have to.