MONZA, Italy — Former Formula One champion Jenson Button will move into semi-retirement next season as McLaren Honda promotes Stoffel Vandoorne into the second driver spot alongside Fernando Alonso.

“Having extended his contract to include 2017 and 2018, he’ll continue to be a senior, influential and committed member of the team, and will remain centrally involved in the development of our cars,” McLaren chairman Ron Dennis said of Button on Saturday. “He’ll also be available to race for us if circumstances require it.”

The 36-year-old Button won the F1 title with Brawn in 2009, and has 15 career victories. He’s in his seventh season with McLaren.

The move comes after Felipe Massa announced on Thursday he will retire from Williams at the end of this season.

“I’m very definitely not retiring,” Button said. “I’m contracted for both 2017 and 2018, I intend to work hard on car development, and I’m sure I’ll get behind the wheel of the new car at some point.”

Vandoorne, a highly sought-after Belgian, has been part of McLaren’s development program since 2013. He finished 10th in his F1 debut when he replaced Alonso at the Bahrain GP this year.