Per the new rule, Shiancoe is eligible to return to practice following week six, and can begin playing in games as early as week eight. While the designation doesn't ensure that Shiancoe will return at some point this year, the team can only use the designation once, so it's a sign that the team could see Shiancoe as part of its plans down the line.
Shiancoe was originally signed by the Patriots on July 24th, but missed nearly all of training camp and the preseason due to an undisclosed injury. With Shiancoe on injured reserve, and Hoomanawanui signed, the Patriots tight end depth chart now looks like this:
1a. Aaron Hernandez ("Flex")
2. Daniel Fells
Reserve/PUP: Jake Ballard
Injured Reserve (with designation to return): Visanthe Shiancoe