It was a low-stress, low-stakes night at FedEx Field as rookie quarterback Robert Griffin III and virtually every other Washington Redskins starter had the evening off to rest and remain unharmed for the regular season.

They watched the team’s less-celebrated rookie quarterback, Kirk Cousins, have another solid outing as the Redskins built a first-half lead and coasted from there to a 30-3 triumph over the Tampa Bay Buccaneers in Wednesday’s preseason finale.

The Redskins finished the exhibition season with a record of 3-1, which means next to nothing as they prepare for the Sept. 9 regular season opener in New Orleans. But Cousins provided a few more glimpses of his NFL promise after starting Wednesday’s game with veteran Rex Grossman as well as Griffin sitting out.

Cousins helped the Redskins to a 16-0 halftime advantage. He and the Redskins added to the lead before Cousins gave way to Jonathan Crompton, the quarterback re-signed by the team earlier Wednesday, in the third quarter.

Tailback Evan Royster had a first-half touchdown run for the Redskins. Fellow second-year running back Roy Helu ran for a pair of third-quarter touchdowns. Royster and Helu played extensively for the Redskins while rookie Alfred Morris and veteran Tim Hightower were given the night off.

Newly signed place kicker Billy Cundiff had three field goals for the Redskins, all in the first half, but missed a 46-yard attempt.

Two rookie defensive backs, safety Jordan Bernstine and cornerback Richard Crawford, provided interceptions as they and other young players tried to secure roster spots and roles on the team for the regular season. It was the final audition before Friday night’s deadline for NFL teams to trim their rosters to 53 players to open the season.

Linebacker Bryan Kehl also had an interception for the Redskins, whose defense sacked third-string Tampa Bay quarterback Brett Ratliff five times.

The stands at FedEx Field were mostly empty at kickoff but filled in later on. The announced attendance was 56,555. There wasn’t exactly a great deal of excitement within the stadium for this one, but Cousins at least had another chance to show his skills.

The fourth-round draft pick from Michigan State had said this week that he expected to play a half Wednesday. Instead, he remained in the game well into the third quarter, and he left with a 23-3 lead.

Cousins completed 15 of 27 passes for 222 yards. He didn’t have a touchdown pass and threw an interception. But Cousins set up Royster’s touchdown run in the first half with a 46-yard completion to wide receiver Anthony Armstrong. And Cousins’s 47-yard completion to Brandon Banks in the third quarter set the stage for Helu’s first touchdown dash.

It wasn’t quite as eye-catching as Cousins’s showing in the second preseason game in Chicago, when he played the second half and threw for 264 yards and three touchdowns. And Grossman, not Cousins, still seems likely to be Griffin’s primary backup entering the regular season, because of his experience. But Cousins again demonstrated that he, too, may have the potential to develop into reliable NFL quarterback.

Cundiff had first-half field goals of 39, 27 and 22 yards. It has been a busy week for Cundiff, who was released Sunday by the Baltimore Ravens and signed Tuesday with the Redskins. The Redskins had a training-camp kicking competition between Graham Gano and Neil Rackers. But they released Rackers on Monday, then cut Gano when they added Cundiff Tuesday. The Redskins told Cundiff he would be their kicker entering the regular season.

A few scattered boos could be heard when Cundiff sent his 46-yard try wide right in the second quarter. But he had another chance before the intermission and connected on the 22-yarder as time expired in the first half.

Wide receivers Josh Morgan and Leonard Hankerson also played Wednesday even though both appear to be entrenched in the team’s rotation for the regular season. Banks is trying to join them on the season-opening roster, and had two significant plays on offense, the 47-yard catch and a 43-yard run that led to Helu’s second touchdown.