With QB Graham Harrell promoted to the 53-man roster last week (and apparently staying there this week despite QB Aaron Rodgers's return) and practice squad WR Terrance Smith placed on I.R., the Packers had two open spots on their practice squad. They've now filled them both according to Packers.com.
G Adrian Battles was a four-year starter at Minnesota State (Division II) and at 6'3" 318 lbs. is quite the wide load. My guess is that he's needed as the scout team's right guard if the brief cameo by OL T.J. Lang at left guard against the Lions is a sign they want to see him practice more on the left side.
S Michael Greco is a former college quarterback making the transition to defense. Not everyone's transition to defense is as smooth as CB Sam Shields's, and Greco must be pretty raw to his new position. But he's very tall (6'3") for a defensive back, and they obviously saw something in him from his last stint on the practice squad. With S Anthony Smith done for the season with an ankle injury, they apparently need another body in the secondary at practice.