Barcelona return to La Liga action on Sunday with lowly Alaves the visitors to Camp Nou.

Ernesto Valverde’s side are fresh from their midweek passage through to the Copa del Rey semi-finals but will have one eye on next Thursday’s tricky last-four tie with Valencia.

However, with Andres Iniesta, Philippe Coutinho and Paco Alcacer all fit and ready for action after injury layoffs, the Barca boss has plenty of questions to answer ahead of Sunday’s clash.

WILL VALVERDE SWITCH BACK TO A 4-3-3?

Due to the absence of Ousmane Dembele, Valverde has for large parts of the season set up his side in a 4-4-2 with the extra man in midfield preferred to natural width.

The system actually resembles a 4-1-3-2 with Sergio Busquets dropping deep to protect the back four and while it’s a step away from the Barca DNA, it’s a formation which has brought Barca success this season.

Indeed, the tweak has been a gateway to afford Lionel Messi plenty of freedom, inspiring their unbeaten run in the league, but the acquisition of Coutinho opens up the possibility of a switch to 4-3-3, which in the Champions League will be richly required.

Iniesta’s return to fitness could see him deployed in the middle three alongside Busquets and one of Paulinho or Ivan Rakitic, while the record buy from Liverpool occupies the left of the forward trio.

However, the move would of course hinge on whether or not Coutinho is fit to start from the off.

TIME TO REST MESSI?

Having contributed to 28 goals in 20 La Liga games (19 via his boot the other nine in assists) the thought of dropping Messi is an unthinkable one.

But consider the fact the Argentine genius has played six full games in 19 days and the complexion shifts.

Given Barca have to tackle a tricky first-leg Copa del Rey tie with Valencia on Thursday and then have their Champions League last-16 clash with Chelsea on the horizon next month, now would represent a good opportunity for Valverde to rest his star man.

Even the 30-year-old himself recognises rotation is a possibility.

“The coach decides,” he said at a promotional event in midweek. “I speak to him often and I have no problem in rotating, like my other teammates.

“Luckily, things are going well and we passed a tough test against Espanyol.

“We’re happy about how things are going, although there is a lot left to play for.”

CAN ALAVES BREACH THE BARCA BACKLINE?

Atletico Madrid and Barca have conceded the least amount of goals (nine) in Europe’s top-five leagues and  Valverde’s stingy side have actually only dropped two goals in their last six La Liga outings.

If Alaves are concerned with the attacking might of Sunday’s hosts, the prospect of scoring themselves is an even more daunting task.

Samuel Umtiti has been a tower of strength all season while Marc-Andre ter Stegen has emerged as one of the premier goalkeepers on the planet.

Contrast that fortune with the lowly visitors and it quickly becomes apparent another three points for Barca will be chalked up.

Alaves have scored just 16 goals in the Spanish top flight this term – the joint lowest – while top scorers Ibai Gomez (four) and Munir (four) have plundered just once in their last six and four games respectively.

Breaching the Barca backline is a tougher task than keeping them out these days.