Real Madrid's business in the summer transfer window raised a lot of eyebrows.

The Champions League winners sold talisman Cristiano Ronaldo to Juventus for €100m and did little business in replacing arguably the world's greatest player.

Dominican Republic striker Mariano Diaz was brought back from Lyon after an impressive stint in Ligue 1 and was handed Ronaldo's prestigious number seven shirt.

Mariano notched 18 goals in 34 appearances over in France and there was some hope that he could elevate his game further back in Spain.

He even scored a cracking goal in the Champions League in the 3-0 win over Roma, but since then it has been all downhill, with injuries limiting him to just five La Liga appearances.

As such, Real Madrid are now actively looking to sign a new striker in January to reduce Karim Benzema, Gareth Bale and Marco Asensio's workloads up front.

According to AS, Los Blancos have a five-man shortlist comprising of two expected names and three wildcard options.

1. MAURO ICARDI (INTER MILAN)

The Argentine has been regularly linked with a switch to the Bernabeu after years of elite level goal scoring in Serie A.

Of the four names on the list, Icardi would be the real headline grabber.

2. TIMO WERNER (RB LEIPZIG)

Germany's number one striker has flirted with a move to Bayern Munich in recent weeks and has been courted by Liverpool in the past.

With Leipzig not in the Champions League, it seems only a matter of time before Werner takes the next step in his career.

3. KRZYSZTOF PIATEK (GENOA)

Before this season, most football fans had never heard of Piatek, but they certainly have now, with the Polish striker scoring 13 goals in just 19 Serie A games.

Pretty much all of Europe's elite have been linked with the 23-year-old and he would likely command a pretty sizeable fee now.

4. BAS DOST (SPORTING LISBON)

One of the more unexpected names on Real's shortlist, but Dost has proven himself as a brilliant, dependable goal scorer out in Portugal.

However, the Spanish club may find it difficult to get Lisbon to sell the 29-year-old for a reasonable price in January.

5. FERNANDO LLORENTE (TOTTENHAM)

Yes, it is a slight possibility. The giant Spanish striker is not in Mauricio Pochettino's plans and he already possesses a wealth of experience in La Liga with Athletic Bilbao.

But Llorente also brings with him zero form in front of goal and a playing style that just isn't Real Madrid. Still, he'd be a cheap stop-gap...