I can assure you that he has always moved that slow. Even before the accident. Also, its not like Seaworld just randomly said "Ok today Tilly will be in shows, bring him out." I happen to know that Seaworld did numerous rehearsals with Tilly in a show situation in the weeks and months leading up to yesterday. So its not like he was just thrown into a show situation with no preparation.
I was in the stadium for the first show and videoed his performance. I saw nothing unusual in his performance. I would not say he was at all "sluggish" after all he is a whale not a rabbit.