Data: NHL; Table: Axios VisualsThe NHL unveiled its return-to-play plan on Tuesday, formally announcing that 24 of its 31 teams will return for a playoff tournament in two hub cities, if and when medically cleared.Why it matters: Hockey is the first major North American sports league to sketch out its plans to return from a coronavirus-driven hiatus in such detail, and it's also the first one to officially pull the plug on its regular season, which will trigger ticket refunds.Yes, but: There are still lots of questions that need to be answered, and it's unclear when — or if — this 24-team tournament will actually take place.Details:Timetable: Commissioner Gary Bettman said teams could conceivably return to training camp on July 1 and begin playing games in late July. However, there are no firm dates, and "anybody who gives you a date is guessing."Testing: The NHL plans to test players every evening for COVID-19, ESPN's Emily Kaplan reports. Bettman says the league could conduct 25,000–30,000 tests.Format: The top four teams in each conference will receive a first-round bye and play in conference-based round robins (three games each) to determine their seedings, one through four. The remaining 16 teams will play best-of-five series to determine which eight will advance to the second round.Length: Bettman said the league and players' union has not decided whether the second round will be best-of-five or best-of-seven. The conference finals and Stanley Cup finals will best best-of-seven, as usual.Draft lottery: Seven teams — the Devils, Sabres, Ducks, Kings, Sharks, Senators and Red Wings — didn't qualify for the playoffs and will enter into a draft lottery along with the eight teams that lose in the first round to determine the first 15 picks in the 2020 draft (so a very good team like the Penguins would have a realistic shot at the No. 1 pick if they lose early).Locations: Under the proposal, games will be played in two "hub cities," with one city hosting the 12 Eastern Conference teams and the other hosting the 12 Western Conference teams. Potential hosts:ChicagoColumbusDallasEdmontonLas VegasLos AngelesMinneapolis/St. PaulPittsburghTorontoVancouverWhat they're saying: The players union said it agreed with the league on the announced plans but made it clear that changes could be made before play is resumed, including to health and safety protocols."If they need to be amended over time, we will amend them. This is a living document, and we have to make sure that logistically, we can actually implement the steps."Donald Fehr, NHLPA executive directorGo deeper: Coronavirus disrupts sporting events around the world