HARRISBURG — Professional sports can resume in Pennsylvania where the governor’s stay-at-home order to stem the spread of the coronavirus is no longer in force, but without spectators, Gov. Tom Wolf’s administration said Wednesday.

Those teams and competitors will be allowed to practice or play in counties where Wolf’s yellow or green designation applies in his stoplight-colored three-phase reopening plan.

To resume, a team or a league must develop a coronavirus safety plan that has been approved by Wolf’s state Department of Health and it must include testing or screening and monitoring of all “on-venue” players and personnel, the administration said.

Fans or spectators cannot be permitted inside or outside the sporting venue property, the administration said.

Wolf is allowing overnight camps and organized youth sports to begin or resume in areas where the green phase is in effect, and is asking that federal guidance be followed to prevent transmission of the virus. Those guidelines do not explicitly bar spectators.

Starting Friday, Wolf is moving eight more counties — Dauphin, Franklin, Huntingdon, Lebanon, Luzerne, Monroe, Pike and Schuylkill — to the yellow phase and 18 mostly rural counties, including the home of Penn State’s main campus in Centre County, to the green phase.

On June 5, Wolf is moving the remaining “red” counties — Philadelphia, Berks, Bucks, Chester, Delaware, Lackawanna, Lancaster, Lehigh, Montgomery and Northampton — to yellow.

Meanwhile, Wolf lifted some dine-in prohibitions for restaurants and bars in counties in the yellow phase, allowing them to serve people seated in outdoor areas.

His administration also said that, under green-phase guidelines, gatherings of more than 250 people are prohibited, including concerts, festivals, conferences, sporting events, movies or performances.

Most businesses serving the public in a building or defined area can only operate at up to 50 percent or 75 percent maximum capacity, depending on the type of business, while also enforcing social distancing requirements.

The NHL announced that it hopes to return at some point this summer with an expanded 24-team playoff format in two host cities.

Pittsburgh is among the finalists to serve as an NHL “hub” and Penguins general manager Jim Rutherford said Wednesday that players will be allowed to work out independently in small groups at the team’s practice facility in Cranberry Township starting as early as next week. Any official NHL-sanctioned “training camp” would not start before July 1.

Rutherford said the team will be meticulous in following health guidelines whenever players return.

“We are very sensitive to what’s going on and we will be very careful with it,” Rutherford said.