SEATTLE -- Yandy Díaz will be shut down from baseball activities for the next 6-8 weeks after a CT scan that he underwent revealed an uncommon hairline fracture to the navicular bone in his left foot, the Rays announced. Diaz is expected to heal fully without surgery, but his regular season is likely over.

“I think that's pretty fair to assume, yeah,” Rays manager Kevin Cash said Friday at T-Mobile Park, where the club begins a three-game series against the Mariners. “Hopefully we've got a long way to go, but they were talking about getting him ramped up, but a lot of things have to go our way.”

Diaz’s timeline rubs right against the beginning of the postseason, which begins Oct. 2 with the American League Wild Card Game. The Rays entered Friday's game against the Mariners in the lead for the second AL Wild Card spot by a half-game over the A’s, and they trail the Indians for the top spot by 3 1/2 games. Their deficit to the Yankees for first place in the AL East has grown to 10 1/2 games.

The Rays diagnosed Diaz’s injury after the third baseman experienced an increase in pain while taking ground balls Tuesday, as he attempted to work his way back from the contusion in that foot that landed him on the 10-day injured list on July 23. Diaz also experienced discomfort before taking grounders while performing exercises, and he still had swelling in his foot after running three consecutive days on a treadmill. The club believes that the fracture was present but undiagnosed when Diaz underwent initial X-rays following the injury.

“Nobody knows, but I think he had the fracture all along,” Cash said. “It was something that was not picked up in the initial X-ray. You get a little more detailed image with the CT scan.”

Nonetheless, it comes as a major blow to a Rays club that is already without key contributors, such starting pitchers Blake Snell, Tyler Glasnow and Yonny Chirinos, second baseman Brandon Lowe and flamethrowing reliever Jose Alvarado.

In Diaz’s stead, Matt Duffy will continue to handle the bulk of the Rays’ innings at third base, with Mike Brosseau available there also. And when Joey Wendle returns from right wrist inflammation, he could be considered, too.

Diaz was in the middle of a breakout season for the Rays after coming over in a three-team trade last December following two subpar seasons with the Indians. His .823 OPS, 117 wRC+ and 1.6 Wins Above Replacement, per FanGraphs, are all career highs, as are his 14 homers, after he hit just one over his first 265 career at-bats.

“The issue with the fracture is that it's in a spot that's pretty delicate and you don't want to make anything worse,” Cash said. “So, do right by him and going forward, but it stinks that he's going to get shut down and miss all this time.”

More injury updates

Lowe had his best day of running so far Friday, Rays’ Major League medical coordinator Paul Harker told Cash. Lowe still needs to progress with his burst running before beginning a Minor League rehab assignment, and the chances of him being activated during the Rays’ next homestand, which begins next Friday, are probably optimistic.

Alvarado (right oblique strain) was scheduled to throw Friday for Triple-A Durham, and the Rays’ immediate pitching needs could prompt the club to recall him if he’s ready. The club could also be prompted to allocate a few more Minor League starts to establish consistency. Trevor Richards, whom the Rays acquired from the Marlins at the Trade Deadline, could be an option also, though Richards threw just one inning for Durham in his first outing since the trade.

Wendle took swings back in Tampa Bay on Friday, but the nature of his wrist injury has the Rays exercising caution on his follow-through, meaning he is still probably a few weeks away.