NFL Network insider Jason La Canfora reported on Friday that the team has informed Gaither he will be placed on season-ending injured reserve.
Gaither has missed all season with a back injury.
The move is likely tied to the return of safety Ed Reed, who missed the first six weeks of the season while on the physically-unable-to-perform list recovering from offseason hip surgery. Reed returned to practice on Wednesday.
La Canfora reported that the Ravens plan to activate Reed and linebacker Brendon Ayanbadejo before Sunday's game, barring a setback.
"I asked him how he's feeling and he said it's unchanged through the weekend," Harbaugh said. "So, that's going to be part of the equation [when Reed and Ayanbadejo return]."
"It was a tough week, but I'll be ready to go," said Heap after Friday's practice, according to The Baltimore Sun. "I'm feeling relatively good right now. So we'll see how it feels Sunday, but right now, I expect to play."