Rivals has commitment lists dating back to 2002. According to their records, Purdue had 21 4-star prospects and 1 5-star prospect from 2002-2018. This includes four straight years without a single 4-star prospect from 2015-18. The only 4-stars Darrell Hazell landed were Gelen Robinson and Danny Etling.
Jeff Brohm just got his third 4-star for the 2019 cycle:
Marvin Grant - 6’2, 193 pound Safety
Martin Luther King, HS, Detroit, MI
Grant is a 4-star safety according to ESPN, Rivals, and 247.