Why have Gunners brought in Konsa?

[Getty Images] Arsenal have spent more than £100m already, bringing in midfielder Bruno Guimaraes from Newcastle (£75m) and Club Brugge winger Christos Tzolis (£34m) during this transfer window. Last season, their extremely well-organised defence - aided by the effective partnership of William Saliba and Gabriel - helped them win their first title in 22 years as they conceded just 27 league goals. But half of their title-winning backline is not going to be fit for the first part of the season. Saliba has been ruled out for an "extended period" with a long-term back issue, which he had been managing last season and which ended his World Cup with France early. Jurrien Timber, the first-choice right-back, is also out for the opening weeks with a groin problem that caused him to pull out of the Netherlands' World Cup squad. That has left Ben White, who has had his own fitness issues in recent seasons, as the Gunners' only fit right-back and 21-year-old Cristhian Mosquera as the only right-sided centre-back to partner Gabriel. It could be argued Arsenal, who also made defender Piero Hincapie's loan deal permanent this summer, could be able to cope without signing another defender. But Mikel Arteta does not seem to like fielding two left-footed players at centre-back - which would happen if White got injured and Mosquera had to move to right-back. Riccardo Calafiori is preferred at left-back by Arteta because of the unpredictability he brings to the team's attack, while Hincapie is left-sided too. Highly rated 16-year-old academy defender Marli Salmon is also on the books, but is most likely to be used sparingly in cup competitions as he continues to develop.