With the transfer window open for almost a month now, we have already seen some massive deals go through. Several high-profile players have already switched clubs, with more seemingly on the way.While attackers have been in high demand so far, there is a feeling that clubs are yet to complete deals for their top targets in defense. As the famous saying goes, attack wins you games but defense wins you titles.Numerous full-backs have been in the news recently, linked with potential future moves. While some have been described as sensible, others have come across as outlandish in the eyes of the public.On that note, let's take a look at five full-backs who could be on the move this summer.#5 Benjamin Mendy - Manchester CityManchester City v Manchester United - Premier LeagueBenjamin Mendy is one of the full-backs who could seek a new challenge this summer.Signed in 2017 by Manchester City from Monaco for a reported £52 million, it is common opinion that the Frenchman has failed to live up to his price tag. Known for his blistering pace and excellent crossing ability, Mendy arrived at the Etihad Stadium amid high expectations.But it is fair to say that Mendy is yet to meet those expectations. Despite the full-back's tenure with City being plagued by injuries, Mendy has found himself on the bench even when fully fit. He has often served as a deputy instead of a starter, with players like Oleksandr Zinchenko and Joao Cancelo getting the nod ahead of him.Inter Milan have turned to Benjamin Mendy as an option at left-back. The Frenchman is out of favour with #ManCity manager Pep Guardiola, and it is thought he would be let go of for the right offer - Inter are weighing up a move.[@sportmediaset via @SempreIntercom]— City Xtra (@City_Xtra) July 5, 2021With the 26-year-old full-back now into the final year of his contract with Manchester City, it seems unlikely that he will make it into the starting line-up for the upcoming season. Several clubs have shown interest in Mendy and his future is well and truly in the balance. With the Premier League season kicking off in about a month, Mendy will be pushing to decide his future soon.#4 Max Aarons - NorwichBristol City v Norwich City - Sky Bet ChampionshipMax Aarons has been seriously impressive over the past two seasons.The 21-year-old signed his full professional contract with Norwich in 2018 and hasn't looked back since. The full-back was a key member of the Canaries' successful campaign in 2018-19 which saw them getting promoted to the Premier League.Max Aarons scored his first goal in nearly two years to send Norwich City to the top of the *Championship*.🗞 Report: https://t.co/C8SIaTqrQT#bbcefl pic.twitter.com/fA6rflp4Mw— BBC Sport (@BBCSport) December 5, 2020In the subsequent season, Aarons continued his fine form and impressed fans and pundits alike with his talent. Although Norwich were relegated from the Premier League, Aarons remained one of the side's silver linings from the season.The young full-back was linked with several clubs last summer, but the Englishman stayed put at Norwich. Aarons continued his impressive performances for the Canaries last season, helping them secure promotion to the Premier League once again.Everton are leading the race to sign Max Aarons - advanced talks and negotiations progressing for the right back. 🔵 #EFCMany clubs are interested as Max Aarons will leave Norwich in the summer - Everton have started contacts since February and hope to reach an agreement soon. https://t.co/phsV5Opcb8— Fabrizio Romano (@FabrizioRomano) April 23, 2021With the Premier League season set to kick off in about a month, interested clubs will need to move quickly if they are to secure the youngster's services.