There has not yet been any official statement from the Seattle Sounders, but Raúl Ruidíaz has joined the team in Atlanta and will almost certainly be available to make his MLS debut on Sunday.
In addition to Sounders fans tracking him down in the Atlanta airport, Ruidíaz updated his Instagram Story with video of the Atlanta skyline that was presumably shot from his hotel room.
In any case, it seems safe to say that Ruidíaz successfully obtained his visa and will be eligible to play. The only remaining question is in what capacity? Sounders head coach Brian Schmetzer has strongly suggested that Ruidíaz will only be used as a reserve as the Peruvian has only gone through one training session with his new teammates.
The Sounders will likely have an abbreviated training session tonight after arriving in Atlanta and Ruidíaz should be able to train fully on Saturday.