The Green Bay Packers signed two players to the practice squad and welcomed back two others from the PUP list to practice Wednesday.

Defensive end Drew Vanderlin and receiver Jeremy Ross were added to fill Green Bay's two vacant practice squad slots, while linebacker Frank Zombo (hamstring) and tight end Andrew Quarless (knee) were back at practice for the first time since being placed on the PUP list before the season.

Two spots on the practice squad were available after offensive lineman Greg Van Roten was activated to the 53-man roster and defensive end Lawrence Guy was claimed by the Indianapolis Colts.

Vanderlin (6-3, 288 lbs.), a graduate of Green Bay Southwest High School and an undrafted free agent out of Michigan Tech, was present during the Packers' rookie tryout camp in April. He finished his career at Michigan Tech second-all time in sacks with 20. He will wear No. 97.

Ross (6-0, 215), second all-time at the University of California in punt return average, worked out for the Packers before the 2011 NFL draft. He was later signed as an undrafted free agent by the New England Patriots, then spent the final 13 games of the 2011 season on the Colts practice squad. Ross will wear No. 10.

Both Zombo and Quarless began the three-week process for coming off the PUP list. The Packers now have that time window to decide whether to activate, cut or place the two on season-ending injured reserve. The same goes for offensive tackle Derek Sherrod (leg), who was not back at practice and is considered behind both Zombo and Quarless medically speaking.

In other practice news, receiver Greg Jennings (groin), linebacker Nick Perry (knee), cornerback Sam Shields (shin) and nose tackle B.J. Raji (ankle) did not participate in Wednesday's practice. Tight end D.J. Williams (hamstring), safety Sean Richardson (hamstring) and running back Johnny White (recently acquired) were able to practice.