The pair missed the 2-1 home win over Fulham on Saturday which extended the table-topping Gunners' perfect start to the season and Arteta was not optimistic about recovering them in time for the clash with Steven Gerrard's side.
"We still have to make another scan, especially on Thomas, to see the length (of absence) but I don't think they'll be available. It's a similar area (to the one that kept Partey out last season), but hopefully not as bad," Arteta told reporters.
Arsenal have made their best start to a Premier League season since 2004-05 and Arteta said he was delighted with the performances that have led to four straight wins.
"The way we are playing, what we transmit as a team and then getting that into winning football matches -- there's the reason why we are where we are," Arteta said.
"There is still a lot to improve. There is room individually and collectively in many areas that we have to do."
The Spaniard expects a tough battle against 15th-placed Villa, who will be looking for their second win of the season.
"I watch the teams and how physical they (Villa) are," Arteta said. "Every game here is a battle for everybody, and we don't expect anything different.
"Villa are a top team, they have a big squad, top quality players and a good manager, and we expect a difficult game again on Wednesday."
