Ollison (undisclosed) has missed back-to-back practices, Vaughn McClure of ESPN.com reports.
A specific reason for Ollison's absence has yet to be identified, but the second-year back's status is one to keep an eye on as training camp progresses. The 23-year-old enjoyed a streak of productive practices last week, but his bid to secure a backup role at running back has been sidelined for the time being.