Alonso's future has been one of the biggest stories of Formula 1's so-called 'silly season,’ the period of the year when the rumor mill starts turning until all the big drivers are signed-up later in the season, with the Spaniard not certain to continue at his current team McLaren.
Alonso doesn't seem to be an option for any of Formula 1's top teams—Mercedes, Ferrari and Red Bull—with most rumors surrounding him either suggesting a longer stay at the struggling McLaren or a possible move to IndyCar as he bids to claim motorsports' Triple Crown.
McLaren and Alonso were long believed to join IndyCar together in 2019, but recent reports have suggested McLaren has scrapped its IndyCar plans amid a management restructure and desire to fully focus on returning its struggling Formula 1 team to competitiveness instead.
Alonso, meanwhile, has now been linked with a possible return to Renault. He previously raced for a former incarnation of the French team between 2003 and 2006 and again between 2008 and 2009, winning both his world titles with the squad.
Source : http://www.thedrive.com/accelerator/22080/renault-f1-not-ruling-out-fernando-alonso-for-the-future