James began his Mavs ' career in the NBA Summer League .
James averaged team highs of 9.0 rebounds and 2.8 blocks , along with 10.2 points , in 5 games .
Beginning his Mavs ' career in the NBA Summer League , James averaged team highs of 9.0 rebounds and 2.8 blocks , along with 10.2 points , in 5 games .