Allen Park — Here are some notes and observations from the third day of the Detroit Lions' mandatory minicamp.
■ If you were looking for hints on Detroit's backfield rotation during the three-day minicamp, there was no clarity provided. Nearly every option got some work with the first-team offense, with veterans LeGarrette Blount, Ameer Abdullah and Theo Riddick seeing the most time.
The Lions will make rookie Kerryon Johnson earn his opportunities, and it's difficult to do that right now, without pads. Right now, the focus in on the mental aspects of the game, making sure he's executing the play calls properly.
With the depth at running back limiting how many opportunities he could have as a rookie, the Lions also are taking a look at Johnson as a kickoff returner. He did a little bit of it at Auburn, returning 26 kicks over two seasons and averaging 25.1 yards.
■ Jamal Agnew's day was cut short by what appeared to be leg cramps, but before he was sidelined, the second-year cornerback was again getting plenty of reps with the first-team defense, operating in the slot. He got picked on a bit early in the session, giving up back-to-back touchdowns during a seven-on-seven red zone drill, one to Golden Tate and another to Kenny Golladay.
Quarterback Matthew Stafford actually connected on short touchdown throws the first four snaps of seven-on-sevens, including a second to Golladay, this time over Teez Tabor, and another to tight end Michael Roberts, a contested grab against linebacker Jonathan Freeny.
■ Undrafted rookie wide receiver Deontez Alexander, a small-school standout with impressive athleticism, seems to be getting more comfortable now that he has a few practices under his belt. He made a trio of nice catches on Thursday.
■ With Tavon Wilson sitting out the team portions following offseason shoulder surgery, Quandre Diggs has continued to see most of his time at safety. But when Agnew was knocked out of action today, Diggs and Nevin Lawson split time in the nickel, freeing up Miles Killebrew to get some extra work with the top defensive grouping.
Killebrew has battled some coverage issues early in preseason, but had a nice breakup on a throw to tight end Levine Toilolo.
■ Undrafted receiver Teo Redding continues to make highlight-reel plays, but had to temporarily leave the field when he went up for a ball and had two defenders crash down on him. Fortunately, after stretching out his legs on the sideline for a few snaps, he was able to return to action.
■ Rookie safety Tracy Walker came up with his first interception of the four open practices, stepping in front of a intermediate throw from backup quarterback Jake Rudock.
Overall, Rudock had a better minicamp than Matt Cassel, but it isn't like last year's backup is putting significant distance between him and his competition. Cassel is understandably still getting a feel for a new offense and teammates, while Rudock's familiarity shows, especially with returning targets such as Jace Billingsley.
■ Former 49ers coach Mike Singletary was in attendance Thursday, checking out how the Lions were using new video boards on the practice field that allow the team to review plays in real-time, as opposed to waiting until a film session later in the day.
Singletary recently took a job as a high school coach in Texas. He said he didn't have a pre-existing relationship with Lions coach Matt Patricia.