Assistant Scott Brooks was named to replace him on an interim basis.
"This was a very difficult decision to make," Thunder General Manager Sam Presti said in a statement released by the team shortly after Friday's 105-80 loss to New Orleans, its 10th straight setback. "It is one that I felt was necessary at this time. I am very appreciative of the hard work and effort that P.J. gave to this team and we wish him the best in his future endeavors."
The Thunder has trailed by at least 30 points in five of the past nine games, has given up at least 100 points in seven straight, ranks 25th in points allowed with a 101.2-point average, and is 29th in the NBA with an 88.9 points per game scoring average.