The Arsenal manager, who is yet to publicly confirm whether or not he will stay at the club beyond this summer, faces Manchester City this weekend with his team languishing in sixth place.
A disastrous run of four defeats in five games has the Gunners off the pace in the race for the top four and Wenger knows that whatever the outcome the club must be active in the transfer market at the end of the season.
“It [the squad] is a very strong basis, but the team needs to be strengthened, of course,” he said at his weekly press conference.
Wenger and Arsenal face City knowing they need to get back on track if they are to make it into next year’s Champions League.
But he confirmed on Thursday they will have to do so without Petr Cech, Lucas Perez and Cazorla with the latter set to miss the remainder of the campaign with an Achilles injury picked up before the turn of the year.
"We have lost Petr Cech. Santi Cazorla and Lucas Perez are out. That should basically be it,” he added.
"We got a message from Alexis. It was a kick. We didn’t know if the ligament was touched or not.
"Bone bruising. He could normally play. [On Santi], I think the season is over for him."