Real Madrid want to improve their attack and Zinedine Zidane has said a return for Cristiano Ronaldo is possible.
Madrid may be looking for a striker who has scored more than 20 goals already this season, including at least five in the Champions League.
Or one that delivers on the big occasion, like a Champions League knock-out game or a crunch La Liga fixture against the league leaders.
They might also think fitness is important, someone who plays the majority of matches, and form, who may have scored something like nine goals in their last 10 games.
Real Madrid already have a striker that ticks all those boxes but Karim Benzema is not Ronaldo and never has been.
When Ronaldo was at the club, Benzema embraced his role of supporting actor and when Ronaldo left, he stepped up to become the lead.
Others were supposed to do the same but failed, like Gareth Bale, who was sent on loan to Tottenham, or Eden Hazard, whose injuries have reduced him to almost an irrelevance.
There were also youngsters, who might have thrived with more responsibility. But the 25-year-old Marco Asensio has stalled while Vinicius Junior and Rodrygo, both 20, are perhaps still too young to be expected to perform consistently for the most successful club in the world.
If Real Madrid want to bolster their attack, they might see that after Benzema, Casemiro is their top scorer on five goals, that Vinicius has three, Hazard and Asensio two each, and Rodrygo none.
Benzema, though, has done what was asked of him. In his last two seasons with Ronaldo, he scored 11 and five league goals. In the two seasons after, he scored 21 in each and at his current rate will end the current campaign with 25.
His strike against Atalanta on Tuesday helped send Real Madrid through to the Champions League quarter-finals after his three previous goals kept them in the title race, two against Elche and a late equaliser against Atletico Madrid.
When Madrid signed Benzema from Lyon for 40 million euros in 2009, the club's president Florentino Perez thought he was a mix of Zidane and Brazil's Ronaldo, both former 'Galacticos'.
But gradually his image was downgraded, the perception of a thrilling, young talent morphing into something less exciting, a team player to be relied on rather than celebrated.
Cristiano Ronaldo was key to that shift, as Benzema's numbers shrank in the shadow of his partner.
And now even as Benzema has become arguably the most important player in this Madrid team, the talk is of Ronaldo returning, the idea the 36-year-old could act as a stop-gap before Kylian Mbappe or Erling Braut Haaland carry the club into a new era in 2022.
In a press conference on Monday, Benzema was asked about the possibility of Ronaldo coming back and while he praised the Portuguese's record at Real Madrid, he also added "but it was three years ago now."
There may have been a message in his answer about his current role too, how he has "the physique to play freely" and can still "play where the ball goes".
At 33, Benzema will know his days are also numbered and that even if Mbappe or Haaland cannot be lured to Madrid, another successor will soon be found.
Real Madrid play away at Celta Vigo on Saturday, hoping to reduce a six-point gap behind Atletico Madrid, who face Alaves at home on Sunday. Barcelona, who are only four points back, travel to Real Sociedad on Sunday night.
Fixtures (times GMT)
Friday
Real Betis v Levante (20:00)
Saturday
Athletic Bilbao v Eibar (13:00), Celta Vigo v Real Madrid (15:15), Huesca v Osasuna (17:30), Real Valladolid v Sevilla (20:00)
Sunday
Getafe v Elche (13:00), Valencia v Granada (15:15), Villarreal v Cadiz (16:15), Atletico Madrid v Alaves (17:30), Real Sociedad v Barcelona (20:00)