Toro Rosso is always viewed as a testing ground for future Red Bull drivers. As a matter of fact, from 2006 till 2009, the team was run by people at Red Bull. But 2010 onwards, the team functions pretty much independently. Hence, Securing parts, human capital and other requisites are more or less the team’s own doing.
Toro Rosso and Honda had been in talks for a possible collaboration, but the deal eventually fell out. With Sauber deal in the trash and McLaren looking elsewhere, Honda was keen to take on some other constructor. And they may have found a partner in Toro Rosso once again.
In the earlier days, Toro Rosso ran with Ferrari power units before switching to Renault for 2014 and 2015. 2016 saw Ferrari back and currently, for 2017, the team runs with renault power. So if made official, It will be a third engine supplier in three seasons for the team.
Sources close to the deal have confirmed to Motorsport.com that the team has agreed a three-year deal from 2018 with Honda, taking it to the end of the current Formula 1 engine regulations cycle at the end of 2020. While the official confirmation will come in later, Honda just might be able to survive in the sport.