Holmes, 26, was taken in the fourth round of the 2013 NFL draft. He was in the final year of his four-year, $2.58 million rookie contract and set to make a base salary of $675,000 for the 2016 season when the Colts waived him back in May.
In 2015, Holmes appeared in nine games for the Colts and was rated by Pro Football Focus as the No. 46 guard out of 81 qualifying players.
Smith, 29, is a former sixth-round pick of the Texans back in 2010. He lasted a little over two years in Houston before he was cut and later claimed by the Rams.
The Dolphins signed him to a two-year contract in 2014, but he lasted just a year in Miami. Smith later signed another two-year, $5.65 million contract contract with the Broncos, but lasted less than a year in Denver.
Smith later returned to the Dolphins to finish out the 2015 season.