He played college football for the Stanford Cardinal and was signed as an undrafted free agent by the Denver Broncos in 2010.
Marinelli attended Boston College High School in Dorchester, Boston, where he was a three-year starter at defensive tackle and two-year starter on offense, where he played tight end as a junior and offensive tackle as a senior.
Having established himself as a solid player, Marinelli started all 12 games at right tackle in his sophomore season.
The Cardinal offensive line allowed a Pac-10 low six sacks on the year, which was the second lowest total in the nation.
Marinelli was claimed off waivers on July 28, 2010, by the Indianapolis Colts.