Eastern Washington and Montana will not meet on the football field next year, the Big Sky Conference confirmed Thursday.

Moreover, their longstanding rivalry – unbroken for 35 years – will now become a hit-and-miss affair, the result of closed-door meetings by school and conference officials last year that eased the way for Idaho to return to the Big Sky.

With the addition of Idaho and the departure of North Dakota in 2018, the conference has revamped its list of “protected rivalries” – those schools guaranteed to play each other every season.

The 2018 and 2019 schedules were finalized in September 2016 and released to the Big Sky’s 13 schools, but not to the public. The Spokesman-Review obtained those schedules on Thursday from Big Sky officials.

The only school adversely affected is Eastern, which now loses all future guarantees of games against the school that most Eagles fans consider to be their biggest rival – Montana.

Currently, Eastern Washington’s protected rivals are Portland State and Montana, but that will change next year when the Griz are replaced by Idaho.

The change in protected rivals was the product of discussions in the summer and fall of 2016. Conference officials have not disclosed how the changes were determined, although it was no secret that Montana and Idaho sought to renew a football rivalry that began in 1903.

Montana released its full schedule on Thursday afternoon. That schedule was accompanied by a statement from UM athletic director Kent Haslam, who said he’s heard “from so many Griz fans about the intensity of the Grizzly-Vandals matchups on the football field. It is great to have the University of Idaho back on the schedule.”

Meanwhile, Eastern will host Idaho on Oct. 27, 2018. Other conference home games are Sept. 22 against Cal Poly, Oct. 6 against Southern Utah and Nov. 10 with UC Davis.

Eastern also has a game at Washington State on Sept. 15, 2018, but has not finalized its full schedule for that season.

With the loss of the Montana game, Eastern will lose a nearly guaranteed home sellout. But athletic director Bill Chaves said he was confident that “our game with Idaho in the years to come will be as attractive to both our fan bases as our game with Montana.”

After the one-year hiatus, the Eastern-Montana rivalry will be renewed on Oct. 26, 2019, in Missoula.

According to Chaves, other options were discussed last year, including increasing the protected rivals to four – thereby preserving the EWU-UM rivalry.

“But then you would have missed playing certain schools for a longer period of time,” Chaves said.

The subject of splitting into two divisions also came up but was never seriously considered.

Ultimately, the format was approved by conference presidents as part of a larger athletics proposal, Chaves said.

Worse for Eastern, it won’t face Idaho in 2019. The reasons are complicated, Loughry said.

“When it was announced Idaho would begin playing football in 2018, we already had 13-team schedules out for 2018 and 2019 (this was before we knew UND was departing),” Loughry said via email. “So for those two years the consultant did what he could to ‘fit’ Idaho in and not cause too many changes to schedules.

“Therefore, Idaho does not become one of EWU’s rivals until the 2020 season.”