Mulligan (undisclosed) did not practice Tuesday, MLive.com's Kyle Meinke reports.
The nature of Mulligan's injury is unclear, but he is not expected to be dealing with anything long-term. Mulligan had been serving as Detroit's primary blocking tight end while Brandon Pettigrew (knee) resided on the PUP list to begin training camp, and was tabbed as the team's No. 2 tight end behind Eric Ebron (leg) on the first unofficial depth chart of the preseason. Now, with Ebron currently sidelined as well, the Lions will be without their top-three overall tight ends for the foreseeable future.