Erling Haaland is Chelsea's main summer target. That's clear as a day. But what if the Blues don't succeed in pursuing the 21-year-old Norwegian sensation? Plan B seems to be mapped out as the London club eyes other world-class footballers to strengthen their squad. Let's take a look.

Robert Lewandowski

First in line is Bundesliga's top scorer for the past 4 seasons. The Polish is the type of player hardly any club would say “no” to. He has a proven track record with 307 goals in Bundesliga & 73 in the Champions League. Just last year, he also won FIFA Best Men's Player award, and he doesn't seem to be slowing down despite his 32 years of age. According to Transfermarkt, his market value currently stands at €60m. That's considerably less than what Borussia expects to get out of Haaland's transfer, but the age factor definitely shouldn't be overlooked here. Lewandowski is a short-term solution compared to Haaland, who's only 21.

Antoine Griezmann

The Frenchman also seems to be of interest to Chelsea. Ever since he departed from Atleti to Barca he hasn't been his old self. The reason for that, among other things, probably lies in the change of the playing system. Some might say it's also because he's not the biggest star in the club like he used to be in Madrid, and thus the game doesn't revolve around him. Don't get me wrong, we're still fully aware of how deadly he can be in front of a goal. He's also a team player who doesn't mind helping the defense and is usually popular in the locker room. There were reports of Barcelona trying to get rid of him (mostly because of his astronomical €400.000-a-week wage) in a swap with Atletico Madrid's Saul. Still, Chelsea seems like a possible destination as well. He's just turned 30 this year, so he still has a few top-level years in him. He's valued at €60m.

Romelu Lukaku

He first joined Chelsea as an 18-year-old boy. The Belgian is a fully grown beast at the peak of his playing career and well sought-after on the transfer market. After a few unsuccessful stints in England with Chelsea, Everton & Manchester United, he finally seems to have found his rhythm in Italy with Inter Milan. He led Inter to the Serie A title for the first time in 10 years scoring 24 goals and providing 11 assists in the competition. Some of Europe's biggest clubs are after him in this transfer window, but rarely any of them can afford his €100m valuation. Chelsea is one of those that could, but are they willing to take a risk with a player who already proved unsuccessful in their system before? Let's wait and see.

Harry Kane

Out of everyone on this list, this is probably the least likely to happen. After all, Chelsea and Tottenham are London rivals for over 100 years. Only three transfers ever happened directly from Spurs to Blues or vice versa. But… you never know. Harry Kane clearly stated he's in search of a new challenge, and even though he'd stay in the same league with a move to Chelsea, they can offer him regular European football and better chances at winning trophies – something Spurs struggle with. Another fact that makes this transfer hard to complete is that Manchester City is interested in Kane. None of the clubs struggle with money, so we could be in for a hard-fought battle for his signature in this transfer window.

Honorable mentions

Saša Kalajdžič of Stuttgart. The youngster netted 17 goals in 36 appearances last season, but the German side reportedly aren't in a rush to sell him. 24 years old, valued at €22m.

Danny Ings of Southampton. Liverpool-reject-turned-Southampton-hero. Not nearly as glamorous of a name as the ones listed above, but Danny proved his quality with 46 goals in 100 appearances for the club from the south of England. He's pretty injury-prone, so that is a concern. 28 years old, valued at €22m.

Domenico Berardi of Sassuolo. The Italian upped his value with good performances at this year's EURO, where he went all the way and won it with Italy. He supplied two assists during the tournament's group stage and has been a Sassuolo's foundation player for the past four seasons. 26 years old, valued at €35m.

Conclusion

We're in for an interesting summer window, that's for sure. Which of these players will end up at Chelsea, if any of these? Do you have your own favorites for a summer move to the London side? Let us know in the comments!