Who will replace Philippe Coutinho for Barcelona in the Champions League?

Luis Enrique liked to rotate during his three years at Barcelona but he knew his best XI when it was mattered. In fact, it was so nailed on that the Catalan press ended up using the term "Gala XI" when he sporadically rolled it out, usually on the big Champions League nights or in Clasicos against Real Madrid.

Ernesto Valverde doesn't like rotating as much and prefers working with a much smaller squad, but it's not clear if he knows his best XI just yet. Not that he has many doubts. There's an increasingly clear "Gala X," but it's so easy in the Champions League.

The one place up for grabs when it really matters is the midfield-forward hybrid role which has been available since the departure of Neymar. In theory, it should be a vacancy filled by £142 million club-record signing Philippe Coutinho (if not Ousmane Dembele, the club's second most expensive signing) but the former Liverpool man is cup-tied in Europe for the remainder of the season.

So against Chelsea on Tuesday, Valverde has one big decision to make. Lionel Messi and Luis Suarez will start in attack; Sergio Busquets, Ivan Rakitic and Andres Iniesta will be behind them. But who will join that quintet of untouchables?

Even without Coutinho, there are as many as six options, with each offering something slightly different.

Paulinho: A goal threat from midfield

Last summer's ugly duckling turned into a swan by Christmas. Eight league goals placed him, for a short while at least, ahead of Cristiano Ronaldo in the scoring charts at one point. In total, Paulinho has made 34 appearances (19 starts) since his €40 million signing from Guangzhou Evergrande. With the Brazilian in the side -- which has been the case away at Juventus and Real Madrid and in both legs of the Copa del Rey semifinal -- Barca play with more of a diamond midfield and tend to carry more of a goal threat when games open up.

Andre Gomes: A more defensive midfield

It has just not quite happened for the Portugal international at Camp Nou. And it's not entirely his fault, either. While he does appear, understandably short of confidence, he's suffered through being shifted around and asked to play a number of roles which aren't necessarily familiar to him. Despite that, and the supporter backlash against him, he often finds himself in the team on tough away days. He has started games at Real Madrid (Super Cup), Atletico Madrid, Athletic Bilbao, Real Sociedad and Real Betis this season. Of his 22 appearances, only 10 have been from the start, but they often come when Valverde wants to keep things tighter with a flat midfield four.

Ousmane Dembele: Speed on the wing

Dembele's first season with Barca is in danger of becoming a write off. Injuries have seen him make just eight appearances for his new club -- with just three starts. The early promise he showed against Juventus in September has been replaced by fears over his fitness and doubts about whether he can deal with the pressure he's under. Yet he can still offer the one thing often lacking from Barca's displays: pure pace. Even now, when he gets on the ball, you expect something to happen. A jinking run, a sprint away from two players... Starting him at Stamford Bridge would certainly be a signal of intent from Valverde.

Paco Alcacer: A poacher in the box

Former Valencia striker Alcacer is very much at his best in the box. With Suarez around, though, he's had to search for life elsewhere. And surprisingly he's often found it on the right. He's worked so hard when given opportunities and has contributed five goals in just nine starts. There was a time around November and December when it looked like he could make the position his. Then he was struck down with an injury just before the Clasico.

Aleix Vidal: An option out wide

Vidal seems to have more lives than a cat. Every transfer window the hammer looks set to come down on his sale, but for various reasons it's never quite dropped. The ex-Sevilla man is more a natural wide option and has made 19 appearances this season. He was the surprise pick in both legs of the Copa del Rey quarterfinal against Espanyol and came off the bench to score against Madrid in December.

Denis Suarez: Creativity and guile

Of the six options, Denis' chances are the most limited. There were high hopes when he rejoined the club in 2016, when he inherited the No. 6 shirt once worn by Xavi Hernandez, but he's struggled to make an impression, let alone tie down a regular spot. Now 24, he could find himself forced out following the signing of Coutinho. Since January, the only two games he has started have been in the Copa del Rey and he's not begun a league game since Dec. 12. It's frustrating because there are aspects of his game which make him perfect for the post-Xavi/Iniesta years at Camp Nou, but something's not quite clicked yet.