Here's a list of every DPOY winner and the number of games he played that year.
1983 - Sidney Moncrief (76)
1984 - Sidney Moncrief (79)
1985 - Mark Eaton (82)
1986 - Alvin Robertson (82)
1987 - Michael Cooper (82)
1988 - Michael Jordan (82)
1989 - Mark Eaton (82)
1990 - Dennis Rodman (82)
1991 - Dennis Rodman (82)
1992 - David Robinson (68)
1993 - Hakeem Olajuwon (82)
1994 - Hakeem Olajuwon (80)
1995 - Dikembe Mutombo (82)
1996 - Gary Payton (81)
1997 - Dikembe Mutombo (80)
1998 - Dikembe Mutombo (82)
1999 - Alonzo Mourning (46)
2000 - Alonzo Mourning (79)
2001 - Dikembe Mutombo (75)
2002 - Ben Wallace (80)
2003 - Ben Wallace (73)
2004 - Ron Artest (73)
2005 - Ben Wallace (74)
2006 - Ben Wallace (82)
2007 - Marcus Camby (70)
2008 - Kevin Garnett (71)
2009 - Dwight Howard (79)
2010 - Dwight Howard (82)
2011 - Dwight Howard (78)
2012 - Tyson Chandler (62)
2013 - Marc Gasol (80)
2014 - Joakim Noah (80)
2015 - Kawhi Leonard (64)
2016 - Kawhi Leonard (72)
2017 - Draymond Green (76)
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On average the DPOY plays 78.8 games.
If Rudy plays every remaining game, he'll finish the season with 56 games played.
Only one player (Zo in 98-99) has played fewer games than Rudy is expected to and won the award. Four players (I've bolded them) have won it while playing fewer than 70 games.
Based on these numbers, I'd say it's obviously unlikely to win the award while playing only 56 (or fewer) games, but it's not impossible; it has happened before, and others have done it in recent years while playing a similar number of games (but, admittedly, still higher than Gobert).
But the right circumstances might be in effect for Rudy to win it. Based on the fact that the usual suspects (Leonard and Green) don't seem to be in the running this time, I'd give Gobert a shot, if 1.) we finish out the season strong (easy schedule will help) and 2.) the advanced stats continue to show how Rudy's defense directly impacts our winning.
I don't think DPOY is completely out of reach, but it'll be tough.