Update: Blizzard corrected itself this morning, saying that competitive mode will be coming later this month, not July.
Previously, tweets from the official Overwatch account (spotted by Eurogamer) reveal that Competitive mode has slipped into mid-to-late July.
@adrianmaturell Sorry about this! Competitive Play will be coming later in *JUNE*, not July. Apologies again for the error. 😖June 1, 2016
@adrianmaturell We'll be introducing our Competitive Play (hopefully) later in July. Stay tuned!May 27, 2016
@jurizar3 We're aiming for mid-to-late July.May 27, 2016
Original: The decision to from the open beta, and the full release of the game, was about as last-minute as it gets. But it sounds like it won't be gone for long: Game Director Jeff Kaplan said in a Q&A video posted today that he hopes to have to have the mode back next month.
“Competitive mode is the current focus of the Overwatch team, and it's the most important thing for us to add to the game right now,” Kaplan says in the video, beginning at around the 9:00 mark.
“Our first big content update for Overwatch will be Competitive mode. I don't want to promise an exact date, because I'm sure whatever date I say right now will be wrong," he continues. "My rough commitment, or 'not-commitment,' would be sometime toward the end of June—middle to end of June. We want to have Competitive mode in. We already have it in internally, in fact we were playing it this weekend and we're starting to get a feel for it.”
Kaplan said changes to Competitive mode will include lengthened seasons, which will probably run for around three months instead of the one month originally planned, and a reduction in the frequency of Sudden Death. More information will be revealed as Competitive mode comes closer to re-launch; Overwatch, don't forget, will be live world-wide .