The 2020 Olympic 10,000m just got a lot more interesting.

Four-time Olympic gold medalist Mo Farah will return to the track for the 10,000m at the upcoming Olympic Games in Tokyo, the 36-year-old defending champion announced in a YouTube video on Friday. The move comes as a surprise after the Brit transitioned to the marathon full-time following the 2017 IAAF World Championships.

Back to Track!! I will focus on the 10,000m next year at the Olympic Games!! ? https://t.co/7LQbfSBAcE

— Sir Mo Farah (@Mo_Farah) November 29, 2019

“Next year I’ve decided, Tokyo 2020, I’m going to be back on the track. I’m really excited to be competing back on the track and give it a go in the 10,000m. Hopefully I haven’t lost my speed,” said Farah.

Seen through the prism of his gold medal chances in Tokyo, this is a smart move. Eliud Kipchoge has the marathon gold under lock and key, while the 10,000m remains much more up for grabs. Joshua Cheptegei won the 10,000m world title in Doha in 2019, the same Joshua Cheptegei who Farah beat for the 2017 world title.

Part of Farah’s decision to return to the surface that he’s had so much success on may be his recent struggles in the marathon. The 2018 Chicago Marathon champion was only eighth last month in his title defense in 2:09:58, over four minutes behind race winner Lawrence Cherono.

Just a day prior, on Oct. 12, Kipchoge became the first man in history to break two hours for the marathon with his 1:59:40 at an exhibition in Vienna. This may not be Farah’s sole motivation for coming back to the track, but there’s no doubt that the 10-time gold medalist is making the smart play for his podium chances in Tokyo.