I don't think we can conclude much from 1 start. His FB velo is still excellent, but you don't get whiffs and K's from FB or FB velo His FB is getting mashed. His control has been good recently, he still generates lots of groundballs. He's not getting whiffs or chase and thus K's this season, even over the last month or 2. His secondaries aren't back to where they were for whatever reason. Cade Horton is getting whiffs and chase but not K's, but Alcantara isn't getting any of the 3.
He has upside but every FO in the league knows that, so I think you're going to pay for that upside. Right now I think he's an average to maybe slightly above-average SP with upside for more.