PHOENIX - The Arizona Diamondbacks want out of their lease at taxpayer-owned Chase Field so they can negotiate with other entities for new stadium, according to documents obtained by 12 News.

Maricopa County's rejection of the Diamondbacks' request has now led to an angry response from the team's chief executive officer, Derrick Hall, declaring that he was "shocked and disappointed" by the county's response.

READ: Maricopa County letter to the D-backs

The team has threatened to sue if the county doesn't give it permission to look for other stadium sites.

The back-and-forth began with Hall's two-paragraph letter March 16 to the Maricopa County Board, asking to modify the Chase Field lease:

"We are requesting that the Maricopa County Stadium District allow AZPB Limited Partnership (the team's owner) the right to take such actions as it deems necessary in order to move and play Diamondbacks' baseball games in a location other than Chase Field."

READ: Hall's letter to Maricopa County

RELATED: 'Chase Field is fine:' Fans react after Diamondbacks want out of stadium lease

County Board Chairman Clint Hickman rejected the Diamondbacks' request in a letter sent Wednesday. Hickman told Hall in a "Dear Derrick" letter that the lease was designed to protect taxpayers from being stuck with an empty stadium they paid for.

The lease put limits on the Diamondbacks, Hickman wrote, "to ensure that the taxpayers, who had paid $238 million in sales taxes to build the stadium (in addition to the District's undertaking an additional $15 million contribution for construction costs), would not be left with an empty stadium" before the 30-year lease expired.

Under the lease, the team can negotiate for a new stadium in eight years, in 2024. The lease expires in 12 years, in 2028.

Hickman added: "The team specifically agreed that all the cities and towns within Maricopa County would be irreparably harmed by any attempted or actual relocation of the team."

RELATED: Cameron Cox: Here's why the D-backs won't be leaving the Valley

Hall said in a letter Thursday that he was "shocked and disappointed" by Hickman's response.

Hall said the team had been working with the county to resolve $187 million in deferred repairs and maintenance. He noted the team's "$8.2 billion in economic benefit ... for Arizona taxpayers. That benefit will substantially increase if we can find a solution to stay in downtown Phoenix."

Hall said the team believed it had an understanding with the county that "the next logical step to free (the county) of this $187 million burden was to agree that the Diamondbacks could at least explore other available stadium options."

He added:

"Although we thought we were making progress, it appears that you have thrown the gauntlet down and have given us no real options at this stage."

12 News has learned that Hall has spoken to Gov. Doug Ducey and Phoenix Mayor Greg Stanton in the last two months about his concerns at Chase Field.

READ: Diamondbacks' January memo to county laying out issues

The team sent the County Board a 15-page memo Jan. 12, with the subject line "Disengagement from the District," laying out its "high level of frustration and dissatisfaction" with the county's stadium district and the team's desire to look for other stadium options.

The memo says, "If permission is not granted, we will ask the court for all appropriate relief."

Hall issued this statement late in the day Thursday:

The Arizona Diamondbacks highest priority is to provide a high-quality experience for our fans and our agreement with the County was designed to ensure that Chase Field delivers on that promise not only on the day it opened, but throughout its lifespan. Our organization will not renege on that commitment and we expect our partners to share that value. Unfortunately, the County has demonstrated that it does not.
“The Maricopa County Stadium District has made clear that it will not be able to meet its obligations to fund financial reserves for capital improvements, which it now estimates to be at least $187 million for the remaining life of the stadium. This spiral is insurmountable and will result in a Chase Field that will no longer be a state-of-the-art facility as our agreement requires and may, in fact, become unsuitable for continued use. We cannot risk being put in that position.
Renovations and stadium projects take time. We would rather act responsibly today to explore alternatives for remaining in downtown Phoenix than turn a blind eye to what we now see clearly as the County’s economic reality. We were asking only for the opportunity to talk with other potential partners, a right that we assert we are due as a result of the County’s existing in ability to meet its responsibilities.
“We want to remain in downtown Phoenix and we would like nothing better than for that to occur at Chase Field, if that is possible. The County is putting in jeopardy the investment that taxpayers have made, that the team has made, and the economic windfall the community has reaped as a result. Again, we only want to do what’s in the best interest of D-backs fans and the franchise.”

Four years ago, the Diamondbacks proposed shifting ownership of the stadium to the city of Phoenix to give the team more of a say in management. 12 News has learned that shift was discussed with the city of Phoenix as recently as January.

The team has also discussed renovations that would reduce the size of the stadium. The price tag on those renovations could approach $100 million to $200 million, 12 News has learned.