The Saints signed Welch to the active roster from the practice squad Saturday, Ross Jackson of WWL Louisiana reports.
With Audric Estime (thigh) moved to IR in a surprise move, the Saints gained an open spot on the 53-man roster. Welch will be the No. 3 tight end due to Oscar Delp (hamstring) being ruled out and will likely participate almost exclusively on special teams and in 13-personnel sets, if he plays at all in the team's Week 1 matchup with the Lions.