Honda has confirmed it is holding customer talks with other teams in Formula One as rumours of a link up with Toro Rosso gather pace.
The Japanese supplier was set to power Sauber in 2018, but its well-documented misery since returning to the sport with McLaren prompted them to continue taking Ferrari engines.
With McLaren also reportedly on the lookout for a new engine partner, Honda is reviewing its plans for next season.
Toro Rosso are being touted as the most likely candidate, despite the fact they have a partnership with Renault in place.
And Masashi Yamamoto, Honda's general manager of motorsport, says discussions are taking place.
"We are talking to teams - other than works outfits like Ferrari and Mercedes - to see if there is an opportunity to do a customer supply deal," he told motorsport.com.
"Meeting the schedule to achieve this for next year will be tough, but we still try to look for the opportunity to do so in 2018.
"If we don't have a customer team, we want to continue with McLaren and then take on a customer team in addition for 2019."