ARSENAL fans have been left stunned by Kai Havertz’s incredible body transformation.The German star returned for the final two games of the season after spending three months out with a hamstring injury.InstagramKai Havertz appears to have undergone an incredible body transformation[/caption]InstagramThe German shared snaps of himself working hard at the gym[/caption]InstagramFans reckon he is bulking up ahead of next season[/caption]And Havertz appears to have kept busy while sidelined by hitting the gym.He shared three snaps of himself hard at work on Instagram alongside the caption: “Loading.”The photos show Havertz lifting weights and doing pull-ups.Fans have compared his new bulging muscles physique with his old look and are convinced he is looking stronger than he ever ahead of next season.One wrote: “The way Havertz has bulked up is crazy.”Another added: “He’s actually a unit right now.”A third wrote: “Mikel Arteta making his players injury-proof.”Yet others are worried Havertz is bulking up to become Arsenal‘s target man No9 when a new striker is high on the club’s summer shopping list.GettyHavertz – pictured here last summer – is likely to see his place in the side put under threat by the potential arrival of a new striker[/caption]JOIN SUN VEGAS: GET £50 BONUSThey have been linked with RB Leipzig’s Benjamin Sesko and Sporting Lisbon’s Viktor Gyokeres.Reports suggest that Sesko, 21, reportedly has a £62million release clause but Arsenal have reservations over a deal.New chief Andrea Berta is a fan of Gyokeres, 26, and he could be available for around £60m.But competition for the Swede is fierce in the form of Manchester United and Atletico Madrid.Join SUN CLUB for the Arsenal Files every Friday plusin-depth coverage and exclusives from The Emirates