ALLEN PARK, Mich. -- Some notes, thoughts and quotes after the first day of training camp for the Detroit Lions:

1. Injuries ruled the day: The Lions couldn’t get through one practice without a key participant suffering an injury. Tight end Eric Ebron, who dealt with injuries all of last season, left practice before the first team portion of drills with what coach Jim Caldwell said he believed was a tweaked hamstring. Caldwell, who was on the practice field the rest of the time, didn’t know the severity, but Ebron’s health will be something to monitor. In his place, the Lions used a lot of Cole Wick in receiving situations with the first team -- including the first rep of 11-on-11 periods. Defensive end Ezekiel Ansah, who is on the physically unable to perform list, watched practice off to the side and didn’t speak with the media following practice. Caldwell said he had no timetable for Ansah’s return to the lineup. With Ansah out, the Lions went with Kerry Hyder and Cornelius Washington at defensive end. Offensive tackle Greg Robinson was taken off the non-football injury list, but he didn’t do much in practice Sunday. Running back Theo Riddick, who is coming off wrist surgery, practiced but wore a red "don’t hit me" jersey -- the same type of jersey Ameer Abdullah wore last training camp.

2. The left tackle situation: While Robinson didn’t practice, he spent a lot of time watching on the side, standing next to injured starting left tackle Taylor Decker. Cyrus Kouandjio got the first-team reps in Decker's place. The Lions signed Kouandjio the same day they traded for Robinson and the two will theoretically battle for the job until Decker returns from his injury. Decker, in declining an interview request, said he’ll talk when he’s able to practice again following shoulder surgery but didn’t say when that would be. Storm Norton, an undrafted free agent from Toledo, took second-team reps at left tackle with Robinson and Corey Robinson sitting out. Cornelius Lucas, who figured to be in the discussion at left tackle, primarily took his reps on the right side with the second team. It’s still way too early to judge anything at left tackle, because of both injuries and the lack of pads. Real judgment will come here starting Tuesday, when pads can come on.

3. Alex Carter showed up: It’s been a rough first two seasons for the former third-round pick out of Stanford. He missed his entire rookie year due to injury and was cut after training camp last season. He spent most of the 2016 season on the practice squad before a late call-up. He was a cornerback then but has spent the past few months transitioning to safety. He ran mostly with the second team on Sunday, with Don Carey and Rolan Milligan hurt, and made the play of the day. Carter, who has added body mass this offseason, read a Jake Rudock pass well and broke to the left side of the field. He timed a jump perfectly to get in front of receiver Jared Abbrederis and then won a battle with him for the ball. It was the most impressive play I’ve seen Carter make during his time with the Lions. He likely is a roster long shot as of now, but a few more plays like that and he could make a push depending how long Carey, a special-teams stalwart, is out.

4. Darius Slay looks sharp: Of all the Lions players, Slay looked the closest to midseason form in practice No. 1. He attached himself to any receiver he faced and was the only cornerback to be consistently competitive in cornerback-versus-receiver one-on-one drills. He also broke up Matthew Stafford’s first pass during team drills of training camp, a deep shot to Marvin Jones. Slay stepped in front of the pass, jumped up and should have intercepted it but let it fall to the ground. Slay’s speed continues to be there and his coverage skills continue to be strong. He also had a good pass defense on Abbrederis in one-on-one drills and only got beat on shorter routes.

5. Drops were prevalent: This wasn’t as much of an issue with the first unit, but the second and third teams had problems holding on to passes from Rudock and Brad Kaaya -- something Caldwell mentioned in his post-practice news conference. Counted at least three drops in practice, including one by running back Dwayne Washington, who had that issue early in camp last year, too. This shouldn’t be a surprise early in training camp, though. If it’s still an issue at this point next week, then it will be a problem.

This and that

Tahir Whitehead lined up at linebacker next to Jarrad Davis, who spent his time as the team’s middle linebacker, as expected. Whitehead figures to be in the lead for the second linebacker spot to play most downs. ... The returner battle had an interesting new competitor Sunday: Golden Tate. Tate was one of six players to be in the punt-return group early in practice along with Jace Billingsley, Jamal Agnew, Abbrederis, TJ Jones and Keshawn Martin. It’d be surprising to see Tate as the returner, but it’ll be worth watching. ... Three players not on PUP or NFI were not present at practice: OL Tony Hills, S Charles Washington and DT Bruce Gaston.