The Blue-White game could give a better indication of where multiple position battles are headed.
"The offensive line room has made some great strides. We've got to keep improving, but I think we're in a great spot right now."
The 27-year-old had seen limited time on the field as a member of the Baltimore Ravens and Arizona Cardinals.
The "seven-figure commitment" provided by West Shore Home and MITER Brands will span over two years.
Clifford threw for 10,661 yards and 86 touchdowns during his Penn State career, and his experience may propel him to a late-round NFL Draft selection.
"He's been invaluable for us."