The 29-year-old midfielder signed a pre-contract with the McDiarmid Park club in January but has controversially expressed a desire to walk away from the deal for what he claims are family reasons.
Saints boss Lomas, who is resigned to losing Scotland international Murray Davidson while Liam Craig has signed a pre-contract with Hibernian, knows his engine room needs refurbishing and is adamant that Brittain's pre-contract has to be honoured.
He expects the player to join his squad for next season - however the issue has been played out in the media for most of the week and shows little signs of abating.
Lomas, though, believes it is simply an additional strand to the game against the Dingwall club who are vying with St Johnstone for a European place.
"We will see where it takes us," he said. "But I rate Richie highly. That is just a sub-plot to the game.
"Once the game starts the players will be trying to win the game. Richard is a good player but Ross County have a lot of good players.
"I have a lot of time for the club and they have been a wonderful story and not just this season either."
Lomas insists his players are raring to get back into post-split SPL action after sitting out last week due to the William Hill Scottish Cup semi-finals. Fourth-placed Saints are five points behind Inverness, who play at Celtic Park on Sunday, and one point ahead of County as the race for European places hots up.
The former Manchester City and West Ham midfielder said: "We just want to get playing again and get the last five games played. It is a huge game for us. I'm sure it is huge for Ross County as well."