Nelson, 33, played 34 games last season for Denver mostly as a backup to Ty Lawson, who was traded to Houston last month. Nelson is expected to play a similar role off the bench in 2015-16 after the Nuggets drafted Mudiay, 19, with the seventh overall pick.
Arthur averaged 6.6 points in 58 games for Denver. Barton thrived after he was acquired in a February deal with Portland. He averaged 11 points and 4.6 rebounds in 28 games for the Nuggets.