Bersin, 27, signed on with the Panthers as an undrafted free agent out of Wofford back in 2012. The Panthers brought Bersin back on a one-year, exclusive rights deal last year before he was waived coming out of the preseason and later signed to the practice squad.
The Panthers re-signed Bersin back in March to a one-year, $690,000 contract before placing him on injured reserve coming out of the preseason.
In 2016, Bersin appeared in 10 games for the Panthers and caught two passes for 17 yards receiving.
Gradkowski, 28, is a former fourth-round pick of the Ravens back in 2012. The Panthers signed Gradkowski to a three-year, $3.15 million contract last year and he set to make a base salary of $875,000 for the 2017.
The Panthers recently placed Gradkowski on injured reserve.
In 2016, Gradkowski appeared in 10 games for the Panthers and is rated by Pro Football Focus as the No. 33 center out of 37 qualifying players.