The 49ers were slated to dress both nose tackles for their Week 7 road matchup with the Tennessee Titans.
Dorsey was listed as questionable because of a hamstring he suffered early in the team's Week 6 win over the Arizona Cardinals.
Dial, placed on the 53-man roster on Saturday, would make his NFL debut. The fifth-round draft pick started the season on the Reserve/Non-Football Injury List and went through his first week of practice this week. He will wear No. 71.
The Titans inactives are as follows: quarterback Rusty Smith, linebacker Zaviar Gooden, linebacker Moise Fokou, linebacker Patrick Bailey, center Rob Turner, tackle Byron Stingily, defensive end Derrick Morgan.