Following two unsuccessful bids for Celtic left back Kieran Tierney, Arsenal are thought to be readying a third offer for one of their main targets this summer. The Gunners have previously dealt with a resistant Celtic team in January of 2015, when the club wanted to sign Virgil van Dijk; however, the Hoops were adamant in keeping their star center back until the summer of that same year. Arsenal ultimately decided that they could not wait any longer and signed Gabriel Paulista from Villarreal instead.

The north London club’s last bid for Tierney, which came a week ago, was said to fall just short of the Scottish team’s valuation for the defender. Celtic want £25 million in cash and the previous Gunners offer was reportedly in the neighborhood of £20 million, with an extra £5 million in performance add-ons. These supplements were supposedly dependent on Arsenal getting back into the Champions League.

With the two clubs not extremely far off in their valuation of Tierney, a deal should be struck before the summer transfer window closes. Signing the 22-year-old defender would be great business for the Gunners. Excelling both defensively and going forward, Tierney is the exact type of defender that the team currently needs.

Current left-sided defenders Sead Kolasinac and Nacho Monreal are certainly decent players, but perhaps not as well-rounded as the Celtic defender. Kolasinac gets forward well, but has his limitations with defending one-on-one. Monreal, on the other hand, has been a very solid signing since joining the Gunners in 2013, but is in the autumn of his career.

Securing Tierney would also allow head coach Unai Emery to officially revert to a back four in defense. The Spaniard was forced to play a back three, while using Kolasinac and Ainsley Maitland-Niles as wing backs for a majority of last season. A back four is Emery’s preferred setup defensively and a fit Hector Bellerin along with Tierney would give the Gunners serious quality in the full back positions.

Assuming Arsenal sign both Tierney and center back William Saliba this summer, the club would have an extremely talented, young defensive quartet for the future. Tierney, Bellerin, Saliba, and Rob Holding are all very highly-rated defenders and have a current combined age of just 21.8.

Although there are some injury concerns for Tierney, £25 million for a player of his capability and potential in this market represents good value. Of course £25 million is not a small fee, but other Premier League full backs have gone for twice as much as the potential Tierney fee in recent years.

Arsenal reportedly do not have the money to spend on transfers that their rivals currently do. However, if the club can lock down the four aforementioned defenders for the future, it could be the start of something special. The Gunners have had issues in defense for some time now and severely upgrading their back line at a somewhat reasonable price would be absolutely immense for the club.