We want to give players some time to learn about and play Orisa before she’s placed into the crucible of Competitive Play.
Principal designer Scott Mercer revealed on the official forums that, “When patch 1.9 releases tomorrow, Orisa will not initially be available for Competitive Play.
“She’ll still be immediately available in Quick Play, the Arcade (including custom games with the competitive ruleset), and Play vs. AI.”
However, if you’re looking to take her into Competitive Play, then you’ll have to wait.