According to Jason Quick of CSNNW.com, the star point guard went "from player to player" to ensure that the $16,000 each player received instead went to trainers, massage therapists and others involved with the team.
Quick also reported that veteran free-agent big man Chris Kaman was the one who inspired this back in 2014-15:
With some Blazers teams, the locker room leadership was not always as generous. Three seasons ago, when veteran Chris Kaman joined the team, he became appalled that the Blazers were keeping their playoff checks. Kaman, who became close with Lillard, told him if he ever led a team he should insist on getting the guys to donate to underscore the importance of unity and having one's back.
Props to Lillard for following through and also to his teammates, who should be commended for their generosity.