The Scottish left-back arrived in north London over the summer nursing an injury and has only appeared in the 5-0 Carabao Cup win over Nottingham Forest and the 4-0 success against Standard Liege in the Europa League so far.
However, Emery has now confirmed that he is fit for action when the Gunners travel to Sheffield United on Monday.
"He is ready to play," he told reporters.
Clarke 'hopeful' of Tierney return for England clash
"Now we have two options in that left-back role with Sead Kolasinac and him. We're going to play a lot of matches after Monday. We will need every player.
"It depends how he comes into the first training with us, Sead, after his international matches. We now have two players in that position and we can use one on Monday, it depends how they are, one or the other."
Arsenal fans will be looking forward to the return to fitnes of Tierney, along with his right-back counterpart Hector Bellerin, who has similarly made just two appearances this term after an ACL injury in January.
Arsenal’s Tierney out for up to six weeks
Tierney and Martinelli return to full training with Arsenal