The outside linebacker from South Florida tore his anterior cruciate ligament during rookie minicamp on Saturday and will be sidelined for the year, a person familiar with the injury said Wednesday night on condition of anonymity because the team did not make an announcement.
McKenzie was hurt when he and a running back made contact during a pass coverage drill. He fell and grabbed his right knee, but walked off the field on his own. He did not return for the second session of the day.
The Patriots drafted McKenzie with their second pick of the third round, 97th overall.
With the trade of longtime starter Mike Vrabel to Kansas City in February, the Patriots needed depth at outside linebacker. Adalius Thomas started last year before being injured. Pierre Woods took over for him, then was sidelined himself.
McKenzie started his college career in 2004 as a backup at Michigan State, then transferred to Iowa State, where he started in 2006 after sitting out a year as required by the NCAA. He transferred to South Florida, where he started 24 of his 26 games and led the team in tackles in each of his two seasons.