The 25-year-old has impressed for the La Liga outfit since joining from the Gunners on a permanent basis in 2012.
Arsenal included a buy-back clause in Vela's contract, which is thought to be in the region of £3.3m, and the Mexican believes that the Premier League club will activate it.
"It makes sense they will activate the clause now. A club that sees that a player is performing well for three years and has the chance of having him back for just an extra million," Vela told the Daily Star.
"If Arsenal wouldn't pay that amount they wouldn't be very intelligent. If we put ourselves in their position we will do the same.
"Now, we have to analyse what can be done and how it can be done. And after putting everything in order, we will make a decision about my future; trying to choose the best way to be happy."
Vela has scored 17 goals in all competitions for Sociedad this season.