Theo Riddick is on the Ameer Abdullah plan.

Abdullah, the Detroit Lions' starting running back, spent most of the preseason last year in a red jersey as he recovered from off-season shoulder surgery and the team tried to limit his exposure to contact.

Abdullah played in one preseason game, logged four carries and showed up for Week 1 healthy (only to need Lisfranc surgery after suffering a foot injury in Week 2).

Riddick, coming off double wrist surgery that sidelined him for the entire spring, spent Day 1 of training camp Sunday in a red no-contact jersey and took part primarily in individual drills.

He said he has no idea how long he'll be restricted in practice, but that his wrists feel "good."

"Just excited to be out there on the field doing what you love," Riddick said. "That’s the biggest thing. I’m just trying to enjoy every moment."

A healthy Riddick would give a huge boost to a Lions offense that struggled to get in the end zone at times last season. He's one of the best pass-catching backs in the NFL, and a big part of a three-headed backfield that includes Abdullah and Zach Zenner.

"It's great to see him out there and it’s just kind of a matter of time trying to get him back in the flow, get everything where he feels good consistently," Lions coach Jim Caldwell said. "We’re just trying to hold back on some of the contact early on and we’ll see how he goes. He’s running well, moving well. We just got to watch him a little bit."

Riddick spent most of the team portion of practice watching from the sideline, but several other Lions made impressions on Day 1 of camp:

• First, the Lions have nine players on the physically unable to perform list or non-football injury list, including Ziggy Ansah, Sam Martin and Taylor Decker. Ansah and Decker watched their respective units go through practice Sunday, and Decker spent part of the first 11-on-11 period about 20 yards behind the line of scrimmage going over plays with presumptive Week 1 starter Greg Robinson.

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• Robinson did not take part in team drills after being removed from the non-football injury list earlier in the day. Cyrus Kouandjio took first-team reps at left tackle in his first practice with the Lions — he was flagged for a false start in one period — and undrafted rookie Storm Norton worked with the second-team offense. Cornelius Lucas worked at right tackle with the second team.

• Tight end Eric Ebron left practice with an apparent hamstring injury, leaving Darren Fells and Cole Wick to take first-team reps, and three players — offensive tackle Tony Hills, defensive tackle Bruce Gaston and safety Charles Washington — did not practice Sunday. Washington was dealing with a personal issue and should return Monday.

• Drops were an issue at various times Sunday. Darius Slay had a nice practice, breaking up a pass to Jared Abbrederis in one-on-ones and blanketing Golden Tate on a nine route in the same drill, but he also dropped an easy interception on Matthew Stafford on the second play of full-team drills.

• On offense, Dwayne Washington dropped the first pass thrown in his way in the opening team period, and Jace Billingsley had a drop a few plays later. One drop won't kill either player, but for young guys fighting for time (and in Billingsley's case, a roster spot) they can't afford careless mistakes.

• Alex Carter made a nice interception in a team period later in practice, coming over from his safety spot in the middle of the field to pick off a Jake Ruddock pass intended for Abbrederis. Carter is vying for the fifth safety spot after changing positions from cornerback this off-season.

• Steve Longa, a dark horse to make the team at linebacker, also intercepted a Brad Kaaya pass that was deflected by Des Lawrence.

• Lawrence, an undrafted rookie, had a rough go of it in one-on-ones covering rookie receiver Kenny Golladay. The Lions' third-round pick, Golladay picked up where he left off after a strong spring and burned Lawrence on a double move deep. Pads come on Tuesday, and his development will be closely watched.

• Rookie cornerback Teez Tabor fell in the draft because of concerns about his speed, and those showed up in one-on-ones Sunday when undrafted rookie Michael Rector ran by him on a would-be touchdown in the end zone.

• Lastly, the Lions had a drone flying overhead at practice Sunday. I asked Caldwell about it, thinking it was something the coaches were using to replace their ladder camera, but Caldwell said it was being used by the Lions website. While several teams have used drones to get a different angle for practice film, Caldwell said the Lions don't have any plans to do that. "Nothing replaces the ladder cam," he said.

Contact Dave Birkett: dbirkett@freepress.com. Follow him on Twitter @davebirkett. Download our Lions Xtra app for free on Apple and Android!