Starter Eric Decker suffered a groin strain Wednesday, while reserves Greg Orton and D'Andre Goodwin each hurt an ankle.
Denver is now back to the 90-man roster limit for the first time since camp began. WR Eric Page and CB Coryell Judie had failed their team physicals a week ago and were subsequently released, and a hamstring injury to second-year safety Quinton Carter had prompted the signing of ex-Buff Kendrick Perkins on Saturday.
Seattle had just signed Kenney in May; he had joined the Chargers as an undrafted free agent in 2011 out of Oklahoma but failed to make the 53-man roster.
As a Sooner, Kenney accumulated 55 catches for 812 yards and five touchdowns in two years; he also returned three kickoffs and one punt as a senior.
A Georgia native, the 23-year-old was arrested last November in Athens on suspicion of stealing a woman's purse at one bar, taking her iPhone, credit cards, and car keys, heading to another bar down the street, and using the victim's bank cards to run up a tab.
A gentleman and a scholar.
Whatever - he'll be gone by August 28 at the latest (first cuts).