Toto Wolff has reportedly bought back into struggling F1 team Williams.

The British team, which recently revealed that it is for sale, was actually Wolff's route into Formula 1 when he bought shares in 2009.

Wolff become Williams' executive director in 2012 but joined Mercedes the following year. He sold 20 percent of Williams to an American businessman in 2014 and the remaining 10 percent in 2016.

Former Williams team manager turned journalist Peter Windsor said on Twitter: "Good to see that Toto Wolff yesterday bought back a 5 percent shareholding in Williams.

"The team could be heading in the right direction for the first time in a while."

After making contact with Mercedes, Windsor clarified that Wolff's Williams stake is in fact "a security", adding: "Make of that what you will."

Some are speculating that the news increases the possibility that Sebastian Vettel may be drafted in to head the works Aston Martin team in 2021.

Recently, Wolff bought into Racing Point owner Lawrence Stroll's new venture.

"I think it's possible that Toto and Stroll's father can offer Vettel something," said former F1 driver Ralf Schumacher.

"I don't know if Toto will hate me for saying that."

However, Racing Point boss Otmar Szafnauer has apparently moved to play down the Vettel rumours, insisting: "From our perspective, the headline for next season is the name above the factory doors rather than the names in the cockpit."