Philadelphia restaurants can increase indoor dining capacity from 25% to 50% starting Friday, Health Commissioner Thomas Farley announced Tuesday — though he said dining outdoors remains safer than indoors.

The city has seen two weeks with an average of fewer than 75 new cases a day, allowing health officials to further reopen indoor dining, Farley said. Expanded indoor capacity began earlier this month for restaurants in the rest of the state but had not been approved in Philadelphia, where coronavirus restrictions have been stiffer.

Philadelphia’s outlook was rosier Tuesday than elsewhere, as Pennsylvania, New Jersey, and Delaware all reported a continued rise in new cases; the Phillies became the latest organization expected to soon reduce staff; and Lehigh University suspended all athletics after on-campus cases were reported.

As the city expands indoor dining, its precautionary measures for restaurants remain in place: tables six feet apart; servers wearing masks and face shields; no bar seating; and only four people per table — “we want only household members to be dining together,” Farley said. In addition, under the state’s rules, bar and restaurant owners must self-certify that they are following coronavirus protocols to be allowed to operate at 50% capacity.

Restaurants can also improve ventilation by opening windows and doors, or by optimizing heating and cooling systems. But Farley encouraged restaurants to continue with expanded outdoor dining as well.

“No matter how much restaurants improve ventilation indoors, the ventilation outdoors is going to be much better,” Farley said. “We do think that’s a much safer environment for diners.”

Some restaurant owners weren’t yet sure whether they’d move to 50% capacity, and others haven’t opened indoor dining with even 25% occupancy, saying indoor dining is too risky for them to consider.

Suzanne O’Brien, who heads operations at a group of seven restaurants, said she and managers might consider opening indoor dining at their larger restaurants, such as Royal Boucherie and Khyber Pass Pub in Old City and Cantina Los Caballitos in South Philadelphia, which remain outdoor-only.

But they are leaning toward waiting for colder weather, when patrons will be less likely to want to sit outdoors — and waiting to see whether cases rise again and force the city or state to reimpose stricter capacity rules.

“We don’t want to have to pivot again,” O’Brien said.

For some restaurants outside Philadelphia, reopening with 50% capacity has been an improvement, but not a solution to economic hardship.

Erin Tate, an owner of MaGerks, which has two locations in Montgomery County, said she noticed a slight uptick in sales when they increased occupancy.

But other state restrictions are “really not helping business, only continuing to hurt,” she said, citing the new state rule ending all alcohol sales at 11 p.m. “It makes it hard to manage customers who seem to want to just get back to normal, with all of the different rules. I’m thankful for the increase, but we just want the bar back. It’s just not the same feeling or vibe without it.”

Farley said he was sympathetic to owners but said bar seating was “just too risky right now."

Though Philadelphia’s average number of new coronavirus cases dropped over September, the state as a whole has not yet tamped down the erratic increases seen in the last month. Pennsylvania reported 988 new coronavirus cases on Tuesday, averaging a slightly elevated 881 new cases a day over the last week, according to an Inquirer analysis.

Investigations were started within a day for more than half of the new coronavirus cases in Pennsylvania last week, the Department of Health said in a Tuesday update about its contact tracing efforts. Of the 5,749 cases confirmed last week, the state’s tracers identified 8,927 contacts of the infected people, who can get tested or quarantine to avoid spreading the virus.

The virus has caused such steep financial losses for the Phillies that employees were offered an increased buyout package on Tuesday, two weeks after a first buyout offer aimed at reducing the number of eventual layoffs. “The club hopes that with meaningful participation, any further reduction in the workforce will be less severe,” the Phillies said.

In New Jersey, where officials were working to prevent new cases in Ocean and Gloucester Counties from spreading, the governor reported 505 newly confirmed infections and 10 deaths on Tuesday.

The Northeastern United States, including Pennsylvania and New Jersey, has led the nation in the rise of cases among people 18 to 22, according to new figures from the U.S. Centers for Disease Control and Prevention.

On Tuesday, Pennsylvania State University reported an additional 352 cases since Friday. Villanova University reported 71 active cases, nearly triple the number it reported Friday.

Villanova has 4,945 students living on campus this fall and is holding some classes in person. It is not planning to change course due to the uptick, a spokesperson said.

“Students have been back on campus for nearly eight weeks,” spokesperson Jonathan Gust said. “The university knew there would be increases as the semester went on and prepared for this by putting in place extensive health and safety guidelines and protocols. … We continue to have ample space available for isolation and quarantine.”

At Lehigh University, all athletics training and practices was suspended Tuesday and at least 60 students were directed to quarantine after six new cases were identified, some of them “connected to multiple athletics programs,” the university told the campus community.

College students are also contributing to an increase in cases in Delaware, Gov. John Carney said Wednesday, reporting about a 10% uptick in coronavirus cases this week.

The state is averaging about 109 new cases per day, Carney said.

The state’s contact tracers have found that increased cases among young adults have not come from one event but from general off-campus social activity.

The governor encouraged residents to get tested if they have possible symptoms or exposure and reminded them to get flu shots.

“We need to get as many people tested as possible on a regular basis,” Carney said.

Staff writers Susan Snyder, Julie Coleman, Rob Tornoe, Tom Avril, and Matt Breen contributed to this article.