Barcelona coach Tito Vilanova will undergo surgery on a saliva gland on Thursday after it was confirmed he faces a second battle against cancer.
The 44-year-old, who had a cancerous tumour removed from his throat in November 2011, will also have six weeks of chemotherapy and radiotherapy.
Tito Vilanova factfile
Born 17 September, Bellcaire d'Emporda, Spain
Comes through the Barcelona youth set-up, but never makes the first team
Joins lower-league Figueres
Arrives at Primera Liga side Celta Vigo
Leaves after struggling to hold down a first-team place
Retires after short spells with a number of lower-league clubs, and starts coaching at Barca's youth academy
After a spell as technical director at Terrassa, becomes assistant manager of Barcelona's B team, working under Pep Guardiola
Becomes Barcelona assistant when Guardiola is made manager
Appointed Guardiola's successor
Barca expect Vilanova to be in hospital for up to four days, but "could be able to mix work with his treatment".
Assistant coach Jordi Roura will take charge of the team in the meantime.
In a news conference on Wednesday, Barcelona president Sandro Rosell said: "We want to express our unconditional support to Tito and his family.
"Tito is strong, very strong - he's shown us that and we're convinced that he'll be back with us soon.
"We have complete confidence in the team. The club is very strong and very united, we're capable of overcoming adversity."
Barcelona sports director Andoni Zubizarreta denied that the club would look to bring in a replacement from outside on an interim basis.
"Tito is the coach, and continues to be so," Zubizarreta said, dismissing rumours Barcelona may have contacted Vilanova's predecessor, Pep Guardiola.
Real Madrid posted a message of support for Vilanova on their website, which read: "Real Madrid want to express their support and best wishes for the coach of FC Barcelona, Tito Vilanova, and wish him a very rapid recovery.
"Real Madrid offer their support to his club and to all his family."
Former Barcelona striker Gary Lineker
"Very sorry to hear Tito Vilanova, the Barca coach, is undergoing surgery after a cancer relapse. Thoughts are with him."
Manchester City striker Sergio Aguero
"We support you, #AnimoTito! We wish you the strength to overcome this moment."
Former tennis world number one Rafael Nadal
"All my strength and support for Tito Vilanova! We are all with you to overcome this next hurdle."
Vilanova's 15-year-old son Adria, a member of the club's youth team,
"Many thanks to everyone for the support. You're great, everything will be fine. Greetings."
Who is Jordi Roura?
Jordi Roura, 45, is a former midfielder who made 10 appearances for Barcelona between 1988 and 1991. He coached in Japan before becoming part of Pep Guardiola's technical staff at the club in 2009, analysing opposition teams. He was promoted to assistant manager when Tito Vilanova became head coach in June.
Vilanova was Guardiola's assistant at the Nou Camp before replacing the former Spain midfielder, who has taken a sabbatical from football,
Since taking charge of the Catalan club, Vilanova has won 23 of his 27 matches in all competitions.
The La Liga leaders are nine points clear of second-placed Atletico Madrid after 15 victories in their 16 matches in the Spanish top flight.
They have also qualified for the knockout stages of the Champions League, despite one of their two defeats this season being inflicted by Group G rivals Celtic.
Meanwhile, Barcelona defender Eric Abidal has trained for the first time following a liver transplant nine months ago.
The 33-year-old Frenchman required surgery a year after having a tumour on his liver removed.