Peters was selected at No. 15 overall by the Kansas City Chiefs in the 2015 draft. He was traded to Los Angeles in March 2018.
The 26-year-old did not sign a new contract when he was acquired by the Rams. He's currently in the final year of his deal and will be a free agent in 2020.
Peters was an All-Pro in 2016 but has yet to replicate that level of success. Known for his ball skills and aggressiveness in coverage, he is Pro Football Focus' 16th-ranked cornerback so far this season.
Young, meanwhile, adds stability to the Rams' front seven next to Cory Littleton. The 2018 fourth-round pick out of UCLA is a sure tackler who thrives in run defense.
The deal ultimately set up the Rams' blockbuster trade for Jalen Ramsey, as Los Angeles shipped out its top cornerback shortly before acquiring one of the league's best. The team also placed Aqib Talib on injured reserve Monday.