The 29-year-old frontman was expected to return at 16:00 local time after having had the weekend off, but instead did not arrive until 18:00 and as a result missed the session.
He was fined 10% of his weekly wage, with Sanchez stating that he would not tolerate this kind of behaviour much longer.
Adriano joined Corinthians in March but is yet to make his debut due to injury. However, he could soon be back in the first team as his recovery continues to go well.
