In a corresponding move, the Patriots placed TE Visanthe Shiancoe on injured reserve with a designation to return.
Hoomanawanui entered the NFL as a fifth-round pick of the Rams in 2010. He played under current Patriots offensive coordinator Josh McDaniels with the Rams last year.
Hoomanawanui (6-4, 263) was released by the Rams on Sunday and landed on the Redskins practice squad. The former Illinois target totaled 20 catches for 229 yards and three touchdowns in 16 games with the Rams over the last two seasons.
The Patriots still need to make a corresponding roster move, likely tight end Visanthe Shiancoe heading to injured reserve, sources say. It's possible Shiancoe could be placed on the new short-term IR, making him eligible to return later in the season.
The signing of Hoomanawanui shines a brighter spotlight on how the Patriots have aggressively stocked the tight end position this year, from signing Rob Gronkowski and Aaron Hernandez to extensions, while also claiming Jake Ballard on waivers, and signing free-agents Daniel Fells and Shiancoe.
The Patriots' base offense features two tight ends, and without depth behind Gronkowski and Hernandez in 2011, the team had little insurance in the event of injury. That showed up in the Super Bowl when Gronkowski was less than 100 percent.
The Patriots kept four tight ends on their initial 53-man roster this year, which is a high total.
Thanks to Jim Thomas, the veteran beat reporter covering Hoomanawanui's former team (Rams), we know the correct pronunciation for Hoomanawanui is "Oh-oh-mah-NAH-wah-NEW-ee."