The summer break is not something the fans look forward to. A couple of months devoid of football action can get mundane but the summer transfer window does help keep things interesting. Football fans stay hooked to their devices, scouring through rumours and finding out what their teams are up to in the transfer market.The Covid-19 pandemic hit clubs hard in a financial sense. As a result, top clubs have had to sell some of their best players. In a sense, the pandemic opened up the market in a massive way. So there was no shortage of transfer activity in the summer of 2021.Many high-profile players were available for sale and top European sides were ready to break the bank to bring reinforcements to their squads. The summer of 2021 saw several transfer records broken as well. But have all those investments paid dividends? Not really.Without further ado, let's take a look at five 2021 summer signings who have failed to live up to expectations.#5 Memphis Depay (Barcelona)FC Barcelona v RCD Espanyol - La Liga SantanderRonald Koeman was keen to bring Memphis Depay to Barcelona in the summer of 2020. However, the club's awful financial condition stopped them from making a move for the Dutchman. Koeman was finally able to rope him in as a free agent in the 2021 summer transfer window.Depay got off to a good start to life in Barcelona. But the weight of expectations was perhaps a bit much. After all, he was now the main man in attack for Barcelona and it's difficult to fill the shoes of players like Lionel Messi for obvious reasons.Depay was expected to be prolific in front of goal. He has impressed in spells but has only eight goals and two assists to his name after making 23 appearances across all competitions for the Catalans. While those numbers are not bad, a club like Barcelona need much more than that from their main forward.Sport claims Barcelona are now looking to offload Depay in the summer with new manager Xavi open to selling him.Football Talk@Football_TaIkLuuk de Jong has won the trust of Xavi over Depay, the latter of which is now put on the transfer list instead of De Jong. #FCB [Mundo Deportivo]3:34 AM · Jan 14, 202244121Luuk de Jong has won the trust of Xavi over Depay, the latter of which is now put on the transfer list instead of De Jong. #FCB [Mundo Deportivo] https://t.co/7HNq4sYhfz#4 Georginio Wijnaldum (Paris Saint-Germain)RB Leipzig v Paris Saint-Germain: Group A - UEFA Champions LeagueGeorginio Wijnaldum had established himself as one of the most efficient central midfielders in Europe at Liverpool. The Merseysiders, however, weren't ready to offer a fresh, lucrative deal to a player who had gone past 30 and decided to let him leave last summer as a free agent.Paris Saint-Germain swooped in for him and the Dutchman was expected to become a great addition to their midfield. He was impressive for his national side at Euro 2020 as well, scoring three goals in four appearances in the continental competition.However, Wijnaldum has looked like a shadow of his former self at PSG. Not only has he failed to nail down a starting berth at the club but he has also proven to be an ill-advised signing. He has only started 11 times in Ligue 1 so far, scoring a goal and providing two assists.Wijnaldum has failed to add much to PSG's midfield and he is already being linked with an exit.Barça Buzz@Barca_BuzzWijnaldum was going to receive €1m less at Barcelona than what he earns at PSG in a 3-year contract.• The player continues to reason that he got tired of waiting for a Barça that did not show enough interest in closing the operation.#FCBVia (🟠): @mundodeportivo4:02 AM · Jan 17, 20221275❗Wijnaldum was going to receive €1m less at Barcelona than what he earns at PSG in a 3-year contract.• The player continues to reason that he got tired of waiting for a Barça that did not show enough interest in closing the operation.#FCBVia (🟠): @mundodeportivo https://t.co/HYKo0wrLWN