The factory Yamaha rider has been demoted to the back of the grid for next month's Valencia finale after receiving three penalty points on his licence for causing a crash with Marquez during the Malaysian Grand Prix.
Facing the prospect of starting from the rear of the grid, Rossi, who leads the championship by seven points from Jorge Lorenzo, says the “unfair” penalty has robbed him the chance to land a 10th world title.
The Italian has strongly denied claims that he intentionally kicked Marquez, causing the reigning world champion to fall from his Honda during Sunday's race.
“We need to see if I will go (to Valencia),” Rossi said when speaking to Italian media.
“The sanction is almost definitive: to start last in Valencia equals not having any chance of making it.
“This way the championship is distorted. I gave everything to win this title.
“Losing it on track is one thing, this way hurts a lot more.
“Should it help, Marquez would let Lorenzo through on the last lap (at Valencia).”
The controversial clash during Sunday's race came after Rossi had accused Marquez of trying to hinder his championship efforts against Lorenzo.
Reflecting on his comments, he says it was potentially a mistake to make the remarks about the Honda rider during a press conference last week.
“Maybe it was a mistake (to speak out), but I couldn't keep quiet,” added Rossi.
“When someone wants to screw you, you have to say so.”