Wenger: Wolves have harmed league's credibility
United beat Wolves 3-0 at Old Trafford on Tuesday after the visitors started with 10 changes to the line-up that had beaten Tottenham Hotspur the previous Saturday.
"We will have to compete with Manchester United over 37 games instead of 38," Wenger told the BBC after his side's 1-1 draw at Burnley on Wednesday.
"I believe it is a problem for the international credibility of the Premier League, but it is not my problem, it is a Premier League problem."
The Premier League said on Wednesday they had written to Wolves asking them for "their observations" in relation to the team that took to the field against United.
"Once the observations are received the Board will decide whether any further action is warranted," the Premier League said in a statement.
McCarthy justified his selection, saying that he needed to use his full squad to cope with a busy spell of fixtures, arguing that Wolves fans would understand his decision if they beat Burnley on Sunday.
Some Wolves fans chanted "we want our money back" at Old Trafford as Wolves slipped into the bottom three.