The 25-year-old joined the Spaniards on a permanent basis in 2012 after a successful loan spell, having failed to hold down a regular starting spot at the Emirates.
The Mexican's tally of 14 league goals has attracted the attention of a number of Europe's biggest clubs, but he could rejoin the Gunners thanks to a buy-back clause inserted into his contract.
"One possibility is my clause of €30m (£24.6m), but there's other options and we're looking at that, to see what we can and can't do," Vela told Radio Marca.
"Arsenal can come back for me at €4m (£3.3m) at any time, which is €1m more than Real Sociedad paid. I look at things differently these days and I won't close the door on Arsenal, or any team in England. I think I'm better prepared to play in another country now."
Vela is expected to be named in Mexico's squad for this summer's World Cup finals, where his country will face hosts Brazil, Croatia and Cameroon in the group stages.