It was a different kind of opening day at Yankee Stadium on Friday. 

Opening as a vaccination hub for Bronx residents, the city said 15,000 appointments would be made available in the first week at the stadium. Now, 13,000 slots have been filled. 

Although there was concern about the city not doing enough outreach to get the word out, Mayor Bill de Blasio says the city will be out in communities to spread the word. 

The stadium will be open from 8 a.m. to 8 p.m. and will operate 24 hours a day once it receives enough supply. 

The stadium will only serve Bronx residents. The borough has seen higher rates of COVID-19 cases during the pandemic. 

"This is an important moment. This is about equity, this is about fairness, this is about protecting people who need the most protection because the Bronx is one of the places that bore the brunt of this crisis of the coronavirus,” said Mayor Bill de Blasio. 

Mariano Rivera was also present Friday to spread the word on getting vaccinated. 

"I grew up as a baseball player here at Yankee Stadium and see so many fans that love the game and supporting me and supporting the organization, the New York Yankees, but now, it's time to support you and let you know it's OK to get vaccinated. I'm on line! OK? When my turn comes, I'm on line to get it,” Rivera tells News 12.