Manchester United fear Eric Bailly has suffered a serious knee ligament injury.

Bailly, who has impressed since his summer move from Villarreal, limped off after 52 minutes with what Jose Mourinho believes could be a long-term knee injury.

"He is injured and I am afraid he is badly injured," Mourinho said. "In his knee, in the ligament area. He feels that it is really bad."

Bailly has played in all but one of United's matches this season, winning the club's Player of the Month award for August.

Andrés Iniesta has injured the lateral collateral ligament in his right knee and will miss six to eight weeks.

Iniesta was injured following a challenge from Enzo Perez and left Saturday's match after 14 minutes.

Iniesta is now 32 and has continued to be a productive part of Barcelona's midfield when healthy.

Lionel Messi returned to training on Wednesday and is expected to make his comeback from a groin injury against Deportivo La Coruna on Saturday ahead of next week's visit from Manchester City in the Champions League.

Messi has been sidelined since injuring his groin for a second time this season in the 1-1 draw with Atletico Madrid last month. He's missed wins over Sporting Gijon and Borussia Moenchengladbach and the defeat to Celta Vigo.

Messi first encountered a problem with his groin after Barca's win over Athletic Bilbao in August. Despite that, he still joined up with Argentina and played in their World Cup qualifying win over Uruguay before returning to Spain.

Sergio Ramos will be out for a month with a knee injury suffered in Spain's 2-0 win over Albania in World Cup qualifying.

Ramos was taken off with a knock in the 80th minute of the match, with tests later showing a tear in his knee ligament, Marca and AS have reported.

Ramos could miss as many as six matches for Real Madrid.

Ramos had come in for criticism from sections of the Spanish media after conceding his fourth penalty of the season in Spain's 1-1 World Cup qualifying draw with Italy but played well against Albania.

Luka Modric faces more than a month out of action after an operation to remove a piece of cartilage from his left knee. Modric suffered knee problems during the 14-15 season.

Isco started in Modric's place on Sunday.

"Our player Luka Modric has today undergone an arthroscopy on his left knee to remove a fragment of cartilage of post-trauma origin," the statement said.

"The operation was carried out successfully under the supervision of Real Madrid's head of medical services, doctor Jesus Olmo. Modric will begin his recovery process tomorrow."

Real Madrid were already without Casemiro in midfield.