Roger Federer enjoys "autumn vibes" during  stroll in picturesque Switzerland

Roger Federer gave his fans some Halloween cheer on Sunday by posting a picture on social media of himself strolling through Switzerland.

In the picture, Federer can be seen standing against a scenic backdrop in his home country. The 20-time Slam champion captioned the post with the line: 'Sunday Stroll Autumn Vibes'.

This is Roger Federer's first update on social media since the announcement of the 'Federer Express' - a tram named after him in Basel - late last month.

Despite being inactive, Roger Federer has climbed one spot to No. 14 in the latest rankings

Roger Federer has been inactive since losing to Hubert Hurkacz in the quarterfinals of the 2021 Wimbledon Championships. Last month, Federer even dropped out of the top 10 for the first time since 2017.

However, the Swiss has still moved up one position - to No. 14 - in the latest world rankings which were published by the ATP tour on Monday.

Roger Federer reacts during an interview with Andy Roddick on Day 2 of the 2021 Laver Cup

Despite playing only five tournaments in 2021 and one in 2020, Roger Federer hasn't seen too steep a drop in his ranking. That is largely due to the COVID-adjusted system in place, which lets players retain points from as far back as 2019.

The rankings are expected to return to normal in 2022 though, so Federer's ranking would fall off a cliff unless he registers some strong results at the big events. And doing that might be difficult given that the 40-year-old underwent another procedure on his knee after his Wimbledon loss - his third on the same knee over the previous 18 months.

There is no definite timetable for Federer's return yet, with the recovery expected to take at least a couple of months more. That said, it was a positive sign to see the Swiss without crutches at the recent wedding of Geraldine Guyot and Alexandre Arnault, son of the world's third richest man Bernard Arnault.

Roger Federer has maintained that he does intend to return to the tour, and his fans will be hoping he competes in the Australian Open at the start of the 2022 season. But that may be nothing more than wishful thinking, given that Federer has not been seen on the court in recent weeks.

The 40-year-old remains tied with rivals Rafael Nadal (who is also out for the rest of the 2021 season due to a foot injury) and Novak Djokovic for the most Majors in men's tennis history, at 20 Slams each.