BARCELONA, Spain -- Ernesto Valverde compared Lionel Messi's clash with Chris Smalling to being hit by a truck after leaving the Barcelona forward out of the squad for Saturday's game against Huesca.

Manchester United defender Smalling unintentionally caught Messi in the face, drawing blood, during Barca's 1-0 win at Old Trafford in the Champions League on Wednesday.

Messi, Barca's top scorer this season with 43 goals in all competitions, ended the game with bruising and swelling around his nose and cheek but tests ruled out any serious damage.

Valverde, though, has opted to err on the side of caution and has not included the Argentine in the 18-man squad for this weekend's match against bottom-of-the-table Huesca.

"It's possible that Messi rests," the coach said in a news conference before announcing the squad. "I spoke with him [on Thursday] and he's doing OK after the blow to the face.

"But he was knocked [by the incident]. [It was like] being hit by a truck. We will assess him in training [on Friday] but it's likely that he will rest."

Smalling told BBC Radio 5 Live's Football Daily podcast on Friday that Messi knew there was nothing intentional about the knock.

"We spoke afterwards. We had a brief chat and shook hands," Smallin said.

"He knew it was an accident."

Messi's not the only Barca player who will have the weekend off ahead of the second leg of their quarterfinal against United at Camp Nou on Tuesday.

Sergio Busquets has also been handed a breather, while Luis Suarez and Gerard Pique are both suspended. Ivan Rakitic and Sergi Roberto have both been ruled out with minor problems.

Defender Jean Clair Todibo comes into the squad for the first time since signing in January, while Barca B players Moussa Wague, Riqui Puig and Abel Ruiz have also been called up.

"Huesca is a dangerous game," warned Valverde, whose side have an 11-point lead over Atletico at the top of the table with just seven games to play.

"We have to be switched on. Not because [we are thinking of the second leg against United] but because you always have to think about the next opponent. So, the danger comes from Huesca, who have a lot to play for.

"Yes, there will be changes [to the team], but let's not forget we still need 10 points to be champions. We will make changes but with the aim of putting out a competitive team."