The phone lines are burning up in the East Bay over a move by the Oakland City Council that could throw a wrench into the deal for the Oakland A’s new waterfront ballpark.

At issue is Alameda County’s half share of the 155 acre Oakland-Alameda Coliseum site, which it plans to sell to the A’s for $85 million.

The city of Oakland owns the other half and would retain its share in the site. But some City Council members say the county should sell its share to the city, even though it’s unclear if the city has the money to buy out the county.

The A’s have said that the revenues earned from developing the Coliseum site, where the team now plays, is a key component to financing the ballpark at the Port of Oakland’s Howard Terminal.

Nonetheless, sources said the Oakland City Council instructed the city attorney in a closed meeting before going on summer break to draft a letter to the county opposing the sale and raising the possibility of a legal challenge if the deal goes through.

To date however, no letter has been sent.

“I think they are rattling their sabers,” said Alameda County Supervisor Scott Haggerty.

Oakland council members we spoke with confirmed having voted to send the letter, but declined to comment publicly because the matter is still under discussion.

The A’s declined to comment.

San Francisco Chronicle columnist Phillip Matier appears Sundays and Wednesdays. Matier can be seen on the KPIX-TV morning and evening news. He can also be heard on KCBS radio Monday through Friday at 7:50 a.m. and 5:50 p.m. Got a tip? Call 415-777-8815, or email pmatier@sfchronicle.com. Twitter: @philmatier