CHARLOTTE, N.C. — The Panthers picked up the fifth-year option on wide receiver Kelvin Benjamin and waived safety Tre Boston and four others on Tuesday.

The decision keeps Benjamin, Carolina's first-round pick in 2014, under contract for the next two seasons and will pay him approximately $8.5 million in 2018.

The news comes just days after Panthers coach Ron Rivera expressed concern about Benjamin reporting to off-season workouts "a little heavy."

"We talked about what he has to do, and he's done a great job," Rivera said. "Am I concerned? Yes, because he is heavy. I'm going to admit that right now. But is he working hard? Absolutely."

Benjamin is listed as 6-foot-5 and 245 pounds and has struggled with his weight in the past. However, Rivera disputed a broadcast report last week that Benjamin had ballooned to 280 pounds.

Benjamin started 13 of 16 games last season and had a team-leading seven touchdown catches on 63 receptions for 941 yards.

He missed the entire 2015 season after suffering a knee injury in training camp.

His best season came in 2014 when he set a franchise rookie record with 73 receptions for 1,008 yards receiving and nine TDs.

Along with Boston, the Panthers also waived fullback Devon Johnson, tackles Jordan Rigsbee and Jake Rodgers and cornerback Lou Young.

Boston, the team's fourth-round draft pick in 2014, spent three seasons in Carolina and started 16 games, including 10 in 2016. He had 93 tackles, two sacks and three interceptions last year, including one he returned for a touchdown. Boston became expendable when the Panthers signed free agent Mike Adams earlier this off-season.

Young spent time on the practice squads of Baltimore, Jacksonville and Carolina. He played in six games last season for the Panthers.

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