Manhertz was slated to become a restricted free agent at the start of the 2019 league year.
Manhertz has played in 36 games with eight starts since coming to the Panthers at the end of the 2016 season. He saw action in every game in 2017 and 2018.
In Week 15 of the 2018 season, he scored his first career touchdown on a 50-yard pass from Christian McCaffrey. It marked the longest reception of his career and the first-ever touchdown pass thrown by a Panthers running back.
Manhertz has four career receptions for 69 receiving yards. His blocking efforts have helped the Panthers offense rank fourth in the NFL in rushing each of the last two seasons.
A basketball player at Canisius College, Manhertz was signed as an undrafted free agent by Buffalo in 2014 and spent time with New Orleans in 2015 and 2016 before signing with the Panthers.