The Arsenal manager has revealed Alexis Sanchez has been playing with a "groin problem for some time" to explain his decision to rest the Chilean international for the Champions League game against Borussia Dortmund on Tuesday night.
Having started in every game over the last two months, the Chilean international has played more minutes (1858) in all competitions than any other player in the Premier League, since his £32m summer move from Barcelona.
Sanchez has also been arguably the best Arsenal player during the first part of the campaign, scoring 14 goals in 23 appearances despite not being the number nine.
The stellar performance is even more impressive because, according to Wenger, the former Barcelona star has not been 100% fit.
When questioned about his decision to leave the Chilean international out of the squad for the visit to Dortmund, the manager said: "Not because of the game on Saturday (against Newcastle) but Sanchez had a groin problem for some time, and he has played 27 games."
"Cazorla has played many games, it is more just the number of repetitive games we have."
Arsenal have already guaranteed the qualification for the knockout stage but need Borussia Dortmund to lose to Anderlecht at home for them to top the group.
After a 3-0 drubbing at Stoke on the weekend, Wenger has decided to use a number of fringe players for the European game.
"To make it as simple as possible, I have 11 experienced players and six young players on the bench. That means I have nothing to hide," he confirmed.
Debuchy is back with us and will play, Szczesny is back in goal, Mertesacker, Chambers will play because Gibbs did not travel, Bellerin at left-back. Then you have Oxlade-Chamberlain, Ramsey, Flamini, Podolski, Sanogo and Campbell. The players who needed it stayed behind - like Cazorla, Sanchez, Gibbs, Giroud is not qualified and Welbeck, who could have travelled but recently had a little knee problem, so took advantage of that to rest him."