1: Isaiah Thomas - PG - Boston Celtics
My vote would have gone to Thomas last year, based on his superior raw numbers and efficiency. There weren't any major areas, aside from turnovers, where Williams had better numbers than Thomas. Don't expect that to change either, as Thomas has established a pattern of efficiency in his four years in the league. There isn't a player who comes off the bench in the whole NBA I would want over Thomas. His energy and scoring is exactly what you want from a reserve, size be damned.
2: Dennis Schroder - PG - Atlanta Hawks
Schroder took a big leap from his rookie season, improving his overall play and efficiency. His role as the leader of the Hawks' second unit is cemented, so he'll get plenty of possessions to improve upon last year's 10.0 PPG and 4.1 APG. He's a better passer and defender than the other lead guards on this list.
3: Nikola Mirotic - F - Chicago Bulls
The first-team All Rookie from a year ago will continue to come off the bench in a deep Bulls frontcourt. If he can come anywhere near his post-All Star break numbers from 2014-15 (16.0 PPG, 6.3 RPG on a 56.0 TS%), he just might win the award.
4: Andre Iguodala - G/F - Golden State Warriors
The 2015 Finals MVP came off the bench in all 77 of the regular season games that he appeared in last season, and that probably won't change this year. He's the best two-way player on this list, but probably won't generate the raw offensive numbers to win.
5: Mo Williams - G - Cleveland Cavaliers
Williams, who averaged 14.2 PPG and 6.2 APG last season with Minnesota and Charlotte, probably would have received more votes had he played for two teams relevant to the playoff picture. He'll get that opportunity this year.