Mata was conspicuous by his absence from the Blues' starting XI at Manchester United on Monday night, despite José Mourinho's decision not to field a recognised striker.
There were reports Juan Mata Senior, father and agent of the Spain playmaker, was at the Emirates Stadium for Arsenal's 2-0 Champions League win versus Fernerbahçe on Tuesday night, though Wenger believes recruiting the World Cup winner would be a long shot.
"I like him," said Wenger, who was beaten to the former Valencia playmaker's signature by Chelsea two years ago.
"I watched the game last night and I've heard, like you, Juan Mata could be on the market.
"There is anyway in England a reluctance to sell to each other."
Arsenal have already failed with two bids for Liverpool striker Luis Suárez this summer and Wenger admitted last week there was "no chance" of any deal for the Uruguayan materialising. Chelsea's bid to sign Wayne Rooney from United has all but failed, too.
Mata was linked with a player-plus-cash move to United in July when Chelsea's interest in Rooney became public, but the Europa League winners either he or David Luíz had been offered to the champions.
Twenty-five-year-old Mata was named in the Premier League Team of the Year for 2012-13 and was voted Chelsea's player of the year in his two seasons at Stamford Bridge.