Camp observations: Lions already feeling the heat

Allen Park — Here are some notes and observations from the Detroit Lions’ training camp practice on Friday:

■The first day of camp had to be moved inside after heavy rains hit the area shortly before the team was set to hit the field. The indoor field wasn’t air conditioned, so the team still got an intense workout in hot, humid conditions.

■The Lions opened with three players on the physically unable to perform list. The trio were on the sideline and offensive tackle Corey Robinson was even able to do some work on the side with one of the trainers, indicating he’s close to returning. There was no cast or boot on wide receiver Corey Fuller’s foot, which required surgery last month. Tight end Brandon Pettigrew did have a brace on his injured knee, but appeared to be moving well, jogging across the field between practice segments.

■Linebacker Jon Bostic switched jersey numbers and is now donning the No. 55 worn by Stephen Tulloch the past five years. Speaking of Bostic, he took nearly all the first-team reps at weakside linebacker in place of DeAndre Levy, who opened camp on the active/non-football injury list.

■In one-on-one receiving drills, the defensive backs were prohibited from pressing at the line of scrimmage. This gave an unfair advance to the receivers, tight ends and running backs, who dominated the drill. Marvin Jones, Theo Riddick and undrafted rookie Jay Lee stood out, each consistently getting quality separation and catching almost every pass thrown their way.

■Veteran wide receiver Anquan Boldin stepped right in and worked with the first-team offense. If it wasn’t clear with the $750,000 signing bonus that came along with his one-year deal, he’s here to play a big role.

■Undrafted rookie Charles Washington, who played both cornerback and safety in college, worked as a safety with the third-string defense. He missed minicamp and most of OTAs with an unknown injury.

■Defensive lineman Kerry Hyder, who has been working primarily as a defensive end this offseason, had a strong day rushing the passer in full-team scrimmaging. If he can keep it up, he’ll merit some second-team looks. He’s on the outside looking in when considering the current roster situation, but there’s no one locked into that fourth DE job right now.

■Safety Isaiah Johnson, who got in some first-team work earlier this offseason, was a bit further down the depth chart to start training camp. Still, he made one of the best defensive plays of the day, jumping a Jake Ruddock pass for what should have been an interception.