A week after most of the rest of Massachusetts, Boston is scheduled to enter the third phase of its coronavirus economic restart on Monday.

Under the plan, movie theaters, museums and historical sites, as well as gyms, are among the businesses allowed to reopen with appropriate public health measures in place, including social distancing and mask-wearing.

Boston's plan differs slightly from the state plan. For example, libraries will remain closed for browsing, but card holders can still order books for pickup.

The city is also limiting attendance at outdoor gatherings to 50 people, while the state limit is 100.

“We took an extra week here in Boston, as most people know, to take extra steps due to our unique concerns here in the city,” Mayor Marty Walsh said Saturday.

Professional sports teams can also hold games in Boston starting Monday — without spectators in the stands.

The Boston Red Sox, which have been live-streaming team practice games, are set to welcome opponents into Fenway Park this month. Their pandemic season's home opener against the Baltimore Orioles is scheduled for July 24.

The Boston Celtics are one of 22 teams returning for the NBA pandemic season restart, which is tentatively scheduled to begin July 30.

Last month, the New England Patriots offered high-risk season ticket holders an opportunity to opt-out of the 2020 season while retaining seats for next year. Team leadership said they "remain optimistic" for the return of football with fans in the fall.

Larger venues, like stadiums and nightclubs, won't be open to the public until the fourth and final re-opening phase, "The New Normal," which Baker has said will be contingent on the availability of a vaccine or treatment.

The Massachusetts Department of Public Health reported 172 new confirmed cases of the coronavirus and 14 new deaths on Sunday.

There have now been more than 105,600 confirmed cases and more than 8,100 coronavirus-related deaths in the state.

There are currently 583 people hospitalized with the disease, up from 572 on Saturday. The number of patients in intensive care rose to 93 on Sunday, up from 87 the previous day.

The number of infections is thought to be far higher because many people have not been tested, and studies suggest people can be infected with the virus without feeling sick.

Somerville officials announced Friday it would delay phase three until July 20 at the earliest. Mayor Joseph Curtatone said he's still concerned about transmission of the disease in indoor spaces in the state's most densely populated city.

On Sunday, Encore Boston Harbor became the second of Massachusetts' three casinos to reopen.

Eric Kraus, senior vice president of Encore's communications and public affairs, told WGBH News that Sunday's reopening went smoothly, and there was no confusion from guests as to what precautions were expected.

"We have ample signage throughout, and the entire staff is here directing people," Kraus said. "As you get into the facility and onto our property, you immediately go through a thermal temperature scan. If you don't have a face covering, we provide one for you. There is signage to re-enforce physical distancing and the new procedures and protocols for our property. It's fun, done safely."

The casino will have reduced capacity and high-touch surfaces will be regularly sanitized, according to Encore's website.

Kraus says there was no line of guests waiting outside to enter, as there was last year for the casino's grand opening.

"It's hard to track right now, the number of people who have been through the casino, but it's a good number of people, and everybody seems to be having a terrific time," Kraus said.

Ten of the casino's 15 food restaurants are open and the hotel is open 4 nights a week, from Thursday through Sunday.

Plainridge Park Casino in Plainville reopened last week, and MGM Springfield is scheduled to reopen Monday.

The Associated Press contributed to this report.

Correction: A previous version of this story misidentified the timeline of the New England Patriots’ message to season ticket holders.