The coach has been out of action since mid-December, when he required surgery after being diagnosed with parotid gland cancer for the second time.
Rosell hopes that the former assistant to Pep Guardiola will be able to juggle his chemotherapy while coaching Barca, but insists that Vilanova’s recovery is the priority over footballing matters.
The club president told reporters in Dubai: "He will return to work in 15 or 20 days, but he will be going back and forth from the hospital and he will be resting.
“He's going to combine the treatment with his work. The most important thing is his health. For the moment, football comes second."
Rosell avoided stating that Xavi and Carles Puyol will be given new contracts at Camp Nou, but the chief insisted that he wants the Barca legends to stay with the squad.
"They are among the best players for Barcelona and for Spain, and they are important for society because they are a great example to young people,” he added.
“I hope they will remain at the club in some capacity in the future."
While on the topic of contracts, Rosell also said he believed the fact that two recent signings took pay cuts to join the Blaugrana shows the commitment players have to the Catalan club.
"We have signed two players in Cesc Fabregas and Javier Mascherano who both earn a lower salary than at their previous club,” he said.
“They also paid the commission on their transfer fee. They really wanted to play for us. It's a beautiful thing."