The Blaugrana chief stressed that the Portuguese coach's Supercopa ban must not be lifted, while adding that Pepe should have been sanctioned for his stamp on Messi
The Portuguese coach will have to serve a two-match ban for poking Vilanova in the eye in Madrid's 3-2 defeat in the second leg at Camp Nou, while the then-Barca assistant coach was suspended for one game for his role in the melee.
Spanish sources have suggested that the country's football federation is considering lifting both suspensions, but the Catalan giants have made no secret that they are against the idea due to the different nature of the duo's actions.
"We do not agree that an aggression like the one that our coach suffered goes unpunished," Rosell told reporters. "We are not going to allow it.
"We are more about actions than words, and we will continue to use every legal instrument to defend ourselves.
"It is not correct to look at both cases the same way. Our coach was assaulted, and it seems people are forgetting it.
"Right now, the pardon is just a rumour, the federation has not said anything about it. If the bans are lifted, we will see what we can legally do."
Rosell also commented on Madrid defender Pepe's stamp on Lionel Messi in January, which went unpunished from the Spanish federation's disciplinary committee.
"The fact that Pepe was not punished for what he did to Messi is a scandal," the Blaugrana chief noted.
The president then went on to touch on the protracted transfer saga between Valencia and Barcelona regarding Jordi Alba's transfer to Camp Nou, warning that his club will not pay over the odds for the 23-year-old.
"The fee we are willing to pay will depend on the way negotiations go," he explained. "I do not like when negotiations are public, but they are.
"Alba will be worth what we are willing to pay, what the deal that we may sign will say."
Pep Guardiola decided to leave Barca at the end of the season to take a break from football after a successful four-year period, and Rosell is hopeful that the coach will return to the club as president someday.
"It would close his cycle at the club; from a little boy in La Masia to president, having gone through all the stages," Rosell said.
"I would vote for him, I certainly would."
Barcelona face Madrid in the first leg of this season's Spanish Supercopa on August 21 at Camp Nou, with the return clash at the Santiago Bernabeu one week later.