When Hector Bellerin burst onto the scene at Arsenal as an exciting youngster, he looked destined to become one of the best players in the world in his position. Under Arsene Wenger's tutelage, he made the right-back spot his own as a 20-year-old and turned heads across Europe with a string of eye-catching displays.However, a combination of poor form and injuries have seen Bellerin fall down the pecking order at Arsenal, with Mikel Arteta preferring to use veteran defender Cedric Soares at right-back. He seems to have lost a yard of pace and lacks conviction in the final third, as his career continues to falter despite his best efforts.The Spaniard has featured quite regularly for Arsenal this season, but he looks a shadow of his former self and blows hot and cold far too often to be relied upon. In 31 appearances in all competitions, Bellerin has recorded just four assists, while he has managed to find the back of the net once.According to Fabrizio Romano, Hector Bellerin will leave Arsenal this summer pic.twitter.com/SaAaY5WEmM— Football Updates (@birdiefootball) April 17, 2021Bellerin is just 26 years old and can't be written off completely, but Arsenal are likely to cash in on him this summer to address other areas of concern. There is currently a dearth of quality right-backs in world football, so the Gunners might need to pull a rabbit out of their hat to replace one of their longest-serving players.On that note, here are five players who they could turn to this summer if Bellerin is sold by the club.#5 Ainsley Maitland-Niles | ArsenalArsenal FC v Dundalk FC: Group B - UEFA Europa LeagueAt the start of the season, it looked like Ainsley Maitland-Niles could take Bellerin's spot at right-back. However, the England international was used as a squad player by Arteta, as he was deployed in several positions in the first half of the season.Maitland-Niles secured a short-term loan move to West Bromwich Albion in January to get more game time under his belt. Since moving to the Hawthorns, the versatile Englishman has caught the eye with a handful of energetic displays, proving that his long-term future could well be as a right-back.Arsenal’s Ainsley Maitland-Niles has been awarded Man of the Match for his performance in West Brom’s 3-0 win over Southampton this evening. [Sky]Love that, @MaitlandNiles! ❤️ #afc pic.twitter.com/hM5M3wN6nI— afcstuff (@afcstuff) April 12, 2021The 23-year-old is set to return to Arsenal at the end of the season and could well be given a chance to impress at right-back. Arteta is likely to assess his in-house options before dipping into the transfer market, so Maitland-Niles could get an extended run of games at the start of next season.#4 Lucas Vasquez | Real MadridAtalanta v Real Madrid - UEFA Champions League Round Of 16 Leg OneLucas Vasquez is one of the most versatile players in world football and could emerge as an intriguing option for Arsenal this summer. The Spaniard is likely to leave Real Madrid at the end of the season and could secure a transfer for a cut-price fee due to his age and contractual situation.The 29-year-old is primarily a winger, but Zinedine Zidane has used him as a right-back to great effect over the years. Vasquez is a fantastic athlete and is capable of making contributions at both ends of the pitch due to his versatility. If Arsenal decide to make a move for him, he could well be the answer to their right-back woes in the short term.Vasquez is also a proven winner and could be a valuable addition to an Arsenal squad that seems to lack character at the moment.