SANTA CLARA, Calif. -- Under normal circumstances, Monday would have been a work day for the San Francisco 49ers.

Coming off a disappointing showing against the Atlanta Falcons on Sunday, the Niners' usual routine would call for a day-after-loss session to sift through the wreckage. But this week, coach Kyle Shanahan deviated from that regimen, giving his team the day off.

The reason? The 49ers had just returned from a 10-day stay in the Eastern Time Zone that included a win against the Carolina Panthers, a trip to the Greenbrier Resort in White Sulphur Springs, West Virginia, for a week of practice and the loss to the Falcons. If history is any indication, the Niners could use the additional down time to shake off their Eastern time hangover, especially as they prepare for a rematch of Super Bowl LIV against the visiting Kansas City Chiefs on Sunday (4:25 p.m. ET, Fox).

While the Niners have gotten good results from their recent history of extended Eastern trips (they're 8-2 on long trips since 2019), they're almost equally bad in their first game back at Levi's Stadium.

The Niners are 1-3 under Shanahan following a weeklong stay in the Eastern time zone. The lone win came in Week 3 of 2019 against a winless Pittsburgh Steelers team and even in that game, the undefeated Niners were sluggish, overcoming five turnovers to score a last-minute touchdown and claim the victory. They lost to the Falcons (who came in 4-9 to the eventual NFC champion 49ers' 11-2) in Week 15 of 2019, the Philadelphia Eagles (who were winless) in Week 4 of 2020 and the Green Bay Packers last season.

"I think there's an adjustment just like there's an adjustment when we go out there," Shanahan said. "It takes us a while to kind of feel right and get used to the time change. And when you stay out there for as long as we did, the same thing happens coming back, so I don't know if that's a coincidence."

The sample isn't large enough to determine if, indeed, it is a coincidence or something deeper. But, as Shanahan points out, the same reasons the Niners like going east for so long -- a chance to adjust their bodies to the three-hour time difference, avoiding multiple five-plus hour flights in a short span, and the chance to establish and stay in a routine -- can work against the Niners when they attempt to get back to business as usual in the Bay Area.

According to right tackle Mike McGlinchey, the change isn't too bad on the way back, though he acknowledges that he's an early riser, so the time change doesn't affect him as much. Still, he says it's common to find yourself waking up at odd hours for at least the first couple of days after getting back on Pacific time.

"You get to sit in that East Coast slot for almost two weeks," right tackle Mike McGlinchey said. "I think maybe the first day or two you wake up a little earlier than you normally would or you fall asleep a little earlier than you normally would. Other than that, I don't really feel it too bad on the way back."

One other common thread the Niners undoubtedly feel when they get back after a long trip is how different the depth chart always looks upon returning. Just using their two previous trips to the Greenbrier in 2020 and 2021 as examples, the Niners have lost multiple key starters to injuries -- both short- and long-term -- on those trips.

And it happened again this year when cornerback Emmanuel Moseley tore the anterior cruciate ligament in his left knee, defensive end Nick Bosa suffered a groin injury, free safety Jimmie Ward broke his left hand and kicker Robbie Gould bruised his left knee against the Panthers. Making matters worse, cornerback Charvarius Ward (groin), McGlinchey (bruised left calf) and safety Talanoa Hufanga (concussion) are day-to-day this week after coming away with ailments in the Atlanta loss.

That type of attrition is tough for any team to overcome, but it only adds difficulty when combined with the challenges of getting back into a usual daily cadence at home.

"That's why we didn't have a day after a game (Monday)," Shanahan said. "Usually I have the guys all in but I gave it off to them just because we've been away so long. I want them to stay home, get their schedule right, mentally be ready to come in Wednesday, and be with their families a little bit."

In their first game back home, the Niners will have an even taller task against the Chiefs and quarterback Patrick Mahomes.

Given what happened the last time those teams met and the result (the Chiefs' fourth-quarter comeback to beat the Niners and claim the Lombardi Trophy), it's safe to say the Niners should have little trouble finding extra juice to rebound and improve on that 1-3, post-extended-Eastern-time mark.

"That's an interesting stat," linebacker Fred Warner said. "I didn't know that... I guess you put so much effort into trying to acclimate to being on the East Coast and winning out here takes a lot outta you. But I'd say there's a pretty good chance that that's not the case this season."