"This home, this is where our kids come and play, this is where our kids have that freedom," Sunnyside resident Michael Pinson said.
A nearly 30-year agreement to use the land ended early.
The city's parks and recreation department told ABC13 that Houston ISD ended it earlier than anticipated to begin construction of a new career and technology education site.
The HISD site being built on the site is called the HISD South Side Launchpad Career and Innovation Center.
Records show the $100 million project is set to begin construction next March.
According to HISD, it will serve high school students in the area and expand access to career pathways to prepare students for college, careers, and the workforce.
It's set to be completed by September 2028. ABC13 reached out to HISD for comment, but has not heard back.
Still, Sunnyside neighbors are shocked by the sudden closure and say that if they had learned about it earlier, they could've planned.
"The community was willing to put up the fight, and it would've allowed the football team and other programs to find other places to practice and be able to book early enough so that way the teams could actually practice," said Sunnyside super neighborhood president Melanie Young.
Young also said it's the only green space in the community.
For Grimes Park, a grand celebration just three years ago; records show $1.3 million in taxpayer money went into renovations.
"And of course, we have invested in maintaining Grimes Park. I don't think we would have done that with full knowledge if we knew that this park was going to be snatched out from under us so quickly," Houston City Controller Chris Hollins said.
Hollins also told ABC13 that he learned the city was aware of the changes since May.
"Yes, we continued to do everything we can to continue to use that HISD property," Mayor Whitmire said.
City officials added that there are other properties in the community that could be converted into parks, but longtime community member Michael Pinson said he wants the park back now.
"It's my livelihood. I grew up here, watched my kids grow up here, watched everybody's kids grow up here. Where are we going to go after this?" Pinson said.