Allen Park — The Detroit Lions on Thursday hit the field for their first full-speed practice in preparation for Sunday’s game against the New York Giants, and two of their starting defensive backs were not participating.
Cornerback Terrion Arnold (concussion) and safety Kerby Joseph (knee) were not spotted during the portion of Thursday’s session open to reporters. Running back Sione Vaki (ankle) was seen, but he was off to the side during individual drills.
If Arnold and Joseph can’t play Sunday, expect cornerback Rock Ya-Sin and safety Thomas Harper to continue filling in at their respective roles. Ya-Sin has started three games this season. Harper, meanwhile, has started the last four contests in a row.
The Lions only held a walkthrough Wednesday, but offensive tackles Penei Sewell (ankle) and Taylor Decker (shoulder), and safety Brian Branch (toe), were estimated as non-participants. All three players were tabbed as limited participants Thursday.
Cornerback Khalil Dorsey (wrist) had his 21-day practice window opened. He was a full participant Thursday. Dorsey, one of Detroit’s starting gunners, hasn’t played since the Lions beat the Cleveland Browns on Sept. 28. The Lions have now activated or started the practice clock for four players on injured reserve: Dorsey, defensive lineman Marcus Davenport and defensive backs D.J. Reed and Daniel Thomas.
Thomas is back on the 53-man roster. Dorsey, Davenport and Reed are practicing, but not yet activated.
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