The Lions met needs by drafting two offensive linemen, a running back and a fullback, two cornerbacks and a defensive lineman.
Zenner was the first player in FCS history to post three consecutive 2,000-yard rushing seasons.
“Obviously we feel good about all these players,” Mayhew said. “But as we talked about before, these guys have to come in and perform now.”
The 6-foot-8, 344-pound Robinson started every game for the Gamecocks in 2014.
“A lot of teams were telling me they wanted to see me around like 245 to 250 range,” Burton said. “Right now I’m around 248, 250.”
As a senior, Diggs logged 73 tackles, three interceptions and five pass breakups. In his four seasons for Texas, he started 49 games.
The 6-foot-, 230-pound Burton played in all 13 games for Rutgers as a fifth-year senior in 2014.
Wright attributed part of his struggles to late notice from Auburn about what his role on the team would be.
To move into the fourth round, the Lions traded their 2016 third-round pick to the Philadelphia Eagles.
The Lions have one pick each in the fifth, sixth and seventh rounds.