Purdue is one of five Big Ten teams who've never appeared in the College Football Playoff Rankings, the most teams of any power conference…by a mile.
Entering the 2019 college football season, 67 different teams have made at least one appearance in the playoff rankings. Fifty-four of those teams are from power conferences (including Notre Dame), led by Alabama, Clemson, and Ohio State, the only three teams to appear in all 31 rankings.
The Sun Belt is the only conference that's never had a ranked team. The Mountain West, MAC, and Conference USA have each had two ranked teams, while seven of the American's 12 teams have been ranked.
2019 CFB Rankings: No. 1 to No. 130
Here's the full list of teams who've never appeared in the College Football Playoff Rankings: