The 26-year-old signed from Monaco ahead of the transfer deadline and was away on international duty, scoring a hat-trick against Lebanon.
Wenger confirmed the relevant paperwork had not yet been completed, but remained optimistic it would be in time for the striker to feature on Saturday.
Speaking to a pre-match news conference, the Arsenal manager said: "We have an uncertainty still with the visa of Park.
"He is in Paris at the moment, but we hope it will be sorted out tonight.
"He has been away playing against Lebanon and Kuwait. From Kuwait he has flown directly to Paris and should come back tonight."
Arsenal's other deadline signings defenders Per Mertesacker and Andre Santos as well as midfield pair Yossi Benayoun and Mikel Arteta are all expected to be involved as the Gunners aim to kick-start their domestic campaign in the wake of an 8-2 mauling at Manchester United.
"I worked very hard after our last game to get the players in because I had to focus on something that was different," Wenger said.
"I feel it has given the team a lift because everybody knew we were a bit short of quality and number-wise with the number of players we have lost at the beginning of the season.
"Other players have left us too and we were too short to compete on all fronts."