Renault is spending money and recruiting heavily for their factory team.  Mclaren has been sliding backwards.  Renault will be nipping at the front before Mclaren; they are ahead of them now.
There are now three manufacturer teams.  Red Bull now having a works status PU once again.  It doesn't look like Mercedes or Ferrari are interested/have openings.  He is likely looking at Renault and Red Bull.  If he jumped to Renault, Red Bull would take up Sainz once again.
To keep this slightly on topic, I say either Alonso sticks around for another year or leaves for Indy and Norris slides in.
			
			
									
									
		