I thought rosters expanding on Sept 1st can't be used as a tool to circumvent the 10-day rule after optioning someone (and 15-day for pitchers). Someone correct me if I'm wrong though, I could be misremembering.
Nope, I think they were just badly timed posts by doing it on April 1st. Probably should have just waited until April 2nd so people would have believed them.
https://x.com/hgomez27/status/1947853833582817739
There's an option period in the first 35 days of his contract to build him up, and after the first 35 days they have to call him up. They signed him on May 5 so they would have to call him up by June 9 at the latest.