It's fair to say that Kai Havertz's Chelsea career hasn't really got going yet.
After a decent start to the campaign, the £71m signing was hit with COVID-19 in November. Not only did he lose his momentum, but the toll of the virus was clear to see for months. He wasn't himself, and just as Thomas Tuchel arrived to give him a fresh start, he picked up a knock.
After missing four games and spending the Manchester United draw on the bench, Havertz came on for some garbage-time minutes in the 1-0 win over Liverpool, but now it's time to bring him back into the starting lineup.
Havertz is obviously going to be a core part of the first team at some point. Roman Abramovich loves him, and the decision to hire Tuchel was largely based on his ability to get the most out of his fellow German. It's just a matter of time before he comes into the team.
In his absence, Chelsea have been spectacular at everything apart from scoring goals. Against Liverpool, their defence was excellent and the buildup play was astonishing, yet there was just one goal to show for it. For all the excitement surrounding Tuchel's Chelsea, their return of three goals in their last four games is a concern.
Monday's meeting with Everton will see Chelsea come up against the same kind of stubborn, in-form defence that has caused them problems in recent weeks, but Havertz may well be the key needed to unlock it.
In Havertz's absence, Hakim Ziyech has been deployed behind the central striker, but he has struggled to replicate the dazzling form which he produced at Ajax. He has left the creativity to Mason Mount who, while he is a truly exceptional footballer, isn't a primary creator. If that's his job, you're in trouble.
Havertz isn't exactly known for his playmaking either, but what he does bring is a new dynamic to Chelsea's attack. He can pick the ball up from deep, drive at defenders and ask them questions they're not used to. That's what Chelsea need at the minute.
Tuchel might have only been in England for ten games, but he has already become something of a meme on social media among fans who aren't exactly appreciative of his pass-heavy style of play. It's all style with very little substance - a common criticism of predecessor Frank Lampard, too.
Chelsea have been passing their way through teams recently, only to get stuck when they reach the penalty area. That extra oomph just hasn't been there, and that's why Havertz has to be brought back quickly.
You only have to look at the 21-year-old's time with Bayer Leverkusen to see how he's perfect for this Chelsea side. He makes devastating runs, can breeze past defenders with ease and is a fantastic goalscorer - three things Chelsea have struggled with under Tuchel.
His introduction could take Chelsea to the next level against Everton, who are on their own run of three straight clean sheets. It'll take something special to beat them, and without Havertz, you can't confidently say that Chelsea will have that extra je ne sais quoi.
Havertz is clearly fit enough to be involved, so it's time for him to make his long-awaited return to the starting lineup. The future starts now.