Martin, 25, is a former third-round pick of the 49ers back in 2014. After three seasons in San Francisco, the 49ers waived Martin last year and he was later claimed off of waivers by the Browns.
The Cowboys signed Martin to a contract last year only to place him on injured reserve in August.
In 2016, Martin appeared in five games for the 49ers.
Bellore, 28, originally signed on with the Jets as an undrafted free agent out of Central Michigan. Unfortunately, his 2016 season ended with him being placed on injured reserve with an elbow injury.
The Lions cut Bellore loose at the start of the 2017 season only to re-sign him a few days later. He returned to Detroit last year on a one-year contract.
In 2018, Bellore appeared in 14 games for the Lions and caught four passes for 15 yards receiving and no touchdowns.