It is that time of the year again, the summer transfer window, when football clubs look to strengthen their squads and sell the deadwood ahead of the start of a new season.In a year ravaged by the COVID-19 pandemic, most of the major domestic football seasons in Europe ended in August. That meant that the summer transfer window, one of two FIFA-designated periods in a season when football clubs can conduct business, commenced only last month.With clubs' finances getting hit by the pandemic, owing to suspension of the football season for a few months, the 2020-21 summer transfer window has been a highly unusual one.However, that has not deterred some rich clubs to splash out the cash to bring in reinforcements. Chelsea, for instance, have been the most active during this period, spending over €230 million (as on 8th September 2020) in one of the most extensive squad overhauls in recent football history.Due to the pandemic, many players are available at more 'cut' or discounted prices than they would have been during an usual season. Chelsea, themselves, have been massive beneficiaries in this regard. On that note, let us take a look at five players who are likely to have massive seasons in 2020-21.#5 Leroy Sane (Manchester City to Bayern Munich)Leroy SaneLeroy Sane began his professional career with Schalke before moving across the Channel to Manchester City, where he blossomed under the tutelage of Pep Guardiola.The player had said that he chose to join City because they were managed by Guardiola."One of the reasons I decided to join City was Pep Guardiola. I know I will learn a lot under him and now I can take the next step in my career. I followed Pep at Barcelona and at Bayern where he achieved a lot and worked really well with young players. I think he can make me a more complete player," said Sane.The words proved prophetic, indeed. During four seasons at the club, Sane made 139 appearances in all competitions for the English club and scored 39 goals. The winger was at his prolific best in 2017-18, scoring ten goals and notching up 15 assists as Man City produced one of the best-ever seasons in Premier League history.Sane's transformation wasn't an overnight one. He admitted to being overwhelmed during his early days in the English game before he honed his skills to become one of City's vital cogs, especially making use of his pace to set up blistering counterattacks.However, in an injury-ravaged 2019-20 season when Sane played only two games all season after tearing his cruciate ligament, City lost their two-year stranglehold on the Premier League and were eliminated in the Champions League quarter-finals.City did not want to lose one of their prized assets, but Sane refused to extend his contract at the club by two years, perhaps indicating that he sought a challenge elsewhere. Eventually, the player returned to his homeland as Bayern Munich acquired him on a €45 million transfer.Welcome to the #FCBayern family, Leroy! 🤩🗞️ https://t.co/5IjFOfjKPz#ServusLeroy #MiaSanMia @LeroySane19— CHAMPIONS OF EUROPE 🏆 (@FCBayernEN) July 3, 2020How Leroy Sane could lineup at Bayern (Pic courtesy DFL)In a team brimming with talent in various positions, Leroy Sane, could play in the left side of midfield, with Serge Gnabry occupying the other flank and Thomas Muller operating down the middle.Sane could thrive under Bayern Munich manager Hansi Flick's attacking philosophy as his pace upfront could set up scoring opportunities aplenty for himself and for teammates like the perennial Torjagerkanone winner Robert Lewandowski.#4 Timo Werner (RB Leipzig to Chelsea)Timo Werner could hit the ground running at Chelsea.After a career-best season in which he plundered 28 goals in the Bundesliga, where Leipzig finished third, and four more in the Champions League, where the Bundesliga club were eliminated in the semifinals, Timo Werner moved to Premier League club Chelsea.To everyone at @ChelseaFC :I’m incredibly happy to be joining the Blues next season! It feels like the right step for me and I am delighted to become a part of Chelsea FC. Really looking forward to playing for such a fantastic and historic club! See you soon Chelsea fans! 👋 pic.twitter.com/WLcagJCHWt— Timo Werner (@TimoWerner) June 18, 2020The London club under Frank Lampard are in the midst of a massive squad overall after finishing fourth in the Premier League last season with a squad consisting of academy graduates.Werner is known for his acceleration, pace and versatility. He started out as a winger with Schalke before making the centre-forward position his own at Leipzig. With Lampard expected to continue with his preferred 4-3-3 formation with his expensively-assembled squad, Werner could be deployed as the central player in a three-man attack.How Timo Werner could lineup at Chelsea (Pic courtesy Squawka)The 24-year-old scored a goal once every 100 minutes when he was deployed down the middle by Leipzig manager Julian Nagelsmann. But the forward also showed his versatility by looking at ease on the few occasions he played on the wings, where he made use of his blistering pace to make use of marauding opposition full-backs and stretched centre-backs.Werner has also shown his prowess in a No.10 role, which shows that he may be deployed in a bevvy of positions in the attacking-third but would guarantee goals every time.