Well, Polaris/Phoenix was rotating at 1 g when it was a hotel. It's possible it still is; if I was running a Mars mission and had the fuel capacity to go up and down regularly, I'd set up a rotation system where everyone had to spend a proportion of their time on the station in full gravity. I don't know, one week up, three weeks down, it'd depend on the logistics and how much gravity-time it takes to counter the effects of Mars gravity. And more time on the station for anyone who's soon to be rotating back to Earth.Plus, the elephant in the room is whether or not his body could stand it after 9-10 years in .38-g. Earth is 2.5 gees to his physiology, now. He could probably adjust back but it would suck.
If there's another rotating station around Earth, that could be an interesting potential solution. Therapeutic elevator suites that gradually move outward from the axis over days, weeks, or months to let people acclimate back to full gravity. Or just multiple levels, and have people switch rooms once they're ready to "graduate" to a heavier environment.