Silver Surfer is a pretty major character in the Marvel Universe and he has had a place in most of the major cosmic events in the comics. With the Surfer’s film rights being held hostage by Fox as part of the Fantastic Four suite, he’s going to have to be absent from some of the big stories he was a part of while they’re adapted in the Marvel Cinematic Universe. But it looks like Marvel has chosen a substitute in Thor.
In the original Planet Hulk comic storyline, Hulk fought a familiar face in the gladiator arena when he faced Silver Surfer. It was a pretty awesome fight, with the Surfer using his board as a shield. In the animated version he was replaced by Beta Ray Bill, but that wouldn’t work in the MCU since he hasn’t been introduced yet. From the Phase 3 preview on the upcoming Doctor Strange Blu-Ray (now out digitally) the Ragnarok concept art shows that Thor replaces both Surfer and his buddy Beta Ray Bill in the gladiator arena.
This opens up another spot where Thor could replace Surfer in the MCU, and that’s in Infinity War. Surfer Surfer led the charge to 1991’s The Infinity Gauntlet with the set-up issues taking place in his monthly comic. Then when the event began it was Surfer who appeared to Doctor Strange to warn him that Thanos was coming:
Thor: Ragnarok is likely the movie that will lead directly into Infinity War as far as the MCU storyline goes. That would open up Thor to being the one to warn Earth, and as he already knows Stephen Strange it would fit for him to appear in the Sanctum Sanctorum to warn him that THANOS IS COMING!