Barcelona coach Tito Vilanova had throat surgery again Thursday after a tumor on a saliva gland reappeared.

The 44-year-old coach is to have chemotherapy and radiotherapy for up to six weeks. The club did not provide a timetable for his return but said Vilanova might return to the sidelines while continuing treatment.

Assistant coach Jordi Roura will coach the team for Saturday's Spanish league game at Valladolid. Roura has been on the coaching staff since 2009.

"Yesterday was a hard day, but (Vilanova) came to the dressing room and explained everything to us and boosted our spirits," captain Carles Puyol said. "He hadn't even left yet and he was saying he couldn't wait to be back. Today we feel better because the news is good. We have to keep playing the same way, train as hard as we can."

Puyol said the transition to Roura should be smooth.

"He has been working with us for years. He knows the team perfectly," Puyol said. "Our way of doing things won't change. We are in good hands."

Vilanova had surgery to remove a tumor from a saliva gland in November 2011 when he was Pep Guardiola's assistant. Vilanova had chemotherapy and radiotherapy at that time and returned to the squad in 15 days, ahead of schedule.

He took over for Guardiola at the end of last season after five seasons as his assistant, four with the first team and one with the B team.

Under Vilanova, Barcelona is off to its best start, winning 15 of its first 16 league games, a Spanish record. The club leads the standings with 46 points, nine ahead of Atletico Madrid and 13 in front of defending champion Real Madrid.

Barcelona is the favorite for this season's Champions League. On Thursday, Barcelona drew AC Milan in the first knockout round. The opening leg of the two-game series is in Italy on Feb. 20.

The announcement of Vilanova's ailment on Wednesday coincided with the return of defender Eric Abidal. This was his first team practice since his liver transplant eight months earlier.

"The example of Abi, who can already play again, gives strength to the entire group," Puyol said.