The Oakland Athletics will start exploring the possibility of relocating with the blessing of Major League Baseball, a move that could put pressure on local government officials to greenlight a new stadium project that has spent years in limbo, sources familiar with the situation told ESPN.

The A's, who have played in Oakland since 1968, have prioritized building a waterfront stadium in downtown Oakland at the Howard Terminal site. But after years of failed stadium plans -- and weeks after the organization asked for the city council to vote on the $12 billion mixed-use development before its late-July summer recess -- the long-anticipated specter of the A's looking into relocation on Tuesday became a reality.

"The future success of the A's depends on a new ballpark," A's owner John Fisher said in a statement. "Oakland is a great baseball town, and we will continue to pursue our waterfront ballpark project. We will also follow MLB's direction to explore other markets."

The A's are the lone remaining major professional sports team in Oakland after the NBA's Golden State Warriors moved across the bay to San Francisco and the Raiders left for Las Vegas. Their pursuit of a new stadium to replace the now-55-year-old RingCentral Coliseum has included multiple sites in Oakland, dalliances with Fremont and San Jose, and two decades without a groundbreaking.