By Joshua Browne Arsenal manager Mikel Arteta says Jurrien Timber is now overcoming the “last big step” in his recovery from a serious knee injury, hinting the Dutchman will be available to play before the end of the season. Timber joined Arsenal from Ajax in a deal worth an initial £34.5m, potentially rising by another £4m should certain performance related add-ons be met. But any hopes Arsenal had of their new signing hitting the ground running were abruptly halted by a serious injury on the first day of the season. Timber innocuously jarred his knee towards the end of the first half against…