Posted be ESPN.com's Kevin Seifert
Here are two injury-related practice notes for you:
Minnesota quarterback Tarvaris Jackson returned to the field after missing five practices with a sprained left knee. Jackson did not participate in all drills, and Sage Rosenfels worked with the first team throughout the morning. But Jackson is certainly moving in the right direction after saying Tuesday that he would be fully recovered in time to play in the Vikings' preseason opener Aug. 14 at Indianapolis.
In Detroit, safety Louis Delmas was held out of practice because of swelling in his left knee, according to Tom Kowalski of Mlive.com. Fellow rookie Brandon Pettigrew continues to miss practice because of a sore thigh, and defensive tackle Grady Jackson sat out practice because of a knee injury one day after he was activated from the non-football injury list.