Rams rookie review: Week 1

EARTH CITY, Mo. -- A look at playing time and production of each of the St. Louis Rams' drafted rookies and a quick glimpse at the undrafted rookie class in Sunday's 34-6 loss to the Minnesota Vikings.

OL Greg Robinson, first round, No. 2 overall: As expected, Robinson did not start on the offensive line with Davin Joseph and Rodger Saffold handling right and left guard duties, respectively. Also as expected, Robinson found his way into the game when Saffold departed with a neck injury late in the game. Robinson played nine snaps on offense and three as a blocker on special teams. Watching how the offensive line fared without him, it's hard to imagine Robinson couldn't have turned in a similar pass-blocking performance at worst and represented an upgrade in the run game at best.

DT Aaron Donald, first round, No. 13 overall: Donald delivered on some of the promise he showed in the early stages of camp with four tackles, including two for a loss against Minnesota's vaunted run game. Most of his 29 defensive snaps came on clear passing downs as Donald entered on third downs inside with Eugene Sims joining him at tackle and Chris Long and Robert Quinn on the ends. There weren't a lot of bright spots among the members of this class, but Donald had his moments.

DB Lamarcus Joyner, second round, No. 41 overall: The Vikings' run-heavy approach didn't allow for the Rams to be in the nickel much, leaving Joyner with just 23 defensive snaps and a dozen more on special teams. He finished with two tackles on defense and another on special teams in a mostly nondescript debut.

RB Tre Mason, third round, No. 75 overall: Mason struggled in the preseason and doesn't provide help on special teams which rendered him inactive for his first NFL game. Of the team's five running backs, Mason was the only one inactive against the Vikings.

S Maurice Alexander, fourth round, No. 110 overall: In a mild surprise, Alexander was also inactive Sunday. It's not a surprise in the sense that Alexander wasn't expected to help on defense right away, but he figured to help on special teams. Rookie cornerback Marcus Roberson was active instead.

CB E.J. Gaines, sixth round, No. 188 overall: The only rookie to start, Gaines got the call in place of the injured Trumaine Johnson. Gaines played 56 defensive snaps (97 percent of the total) and six more on special teams. In the process, he had three tackles and two pass breakups, nearly coming up with an interception early in the game.

C Demetrius Rhaney, seventh round, No. 250 overall: Rhaney is on injured reserve for the season with a knee injury.

Undrafted rookie roundup: Roberson played 11 snaps on special teams and running back Trey Watts played nine there also, neither registered a tackle in the unofficial statistics. ... Tight end Alex Bayer and defensive lineman Ethan Westbrooks were pregame inactives.