Both players can practice once they are cleared medically. Spencer is still recovering from knee surgery almost a year ago and Leary has a hamstring injury.
The Cowboys have their first practice Thursday.
Dallas placed defensive tackle Amobi Okoye on the active non-football illness list. The former top 10 pick from 2007 is trying a comeback after being out of football last season.
Spencer had a career-high 11 sacks in 2012 but played just the opener last year because of knee trouble that started in the offseason. Leary started all 16 games at left guard in 2013.