The Seahawks returned to action on a sweltering Sunday afternoon following an off day, and the fourth practice of training camp saw two prominent players take to the field for the first time in camp. More on that and other notes from Sunday's practice in our five observations from practice No. 4 of Seahawks camp:

1. Chris Carson is back.

Seahawks running back Chris Carson was back on the practice field after missing the first few days of action to attend to a family matter back home. And not only was Carson back, but in a positive development for a player coming back from a season-ending hip injury, he was moving well, looking like his usual self and not like someone dealing with any lingering injury issues.

Seahawks coach Pete Carroll made it clear earlier this offseason that the team will be cautious with Carson and ease him back into action, but while he may not yet be taking on a full workload, seeing him back on the field and moving like the player who has rushed for more than 2,300 yards in the past two seasons is an encouraging development early in camp.

2. Quinton Dunbar made his debut.

Cornerback Quinton Dunbar, who was acquired in an offseason trade with Washington, practiced with his new team for the first time on Sunday. 

Dunbar came off of the commissioner's exempt list last weekend, but the required level of COVID-19 testing required of players before they can practice meant Dunbar wasn't able to take his physical until Friday or take the field until Sunday. 

Not long after the Seahawks took the field, Dunbar was getting some hands-on, one-on-one coaching from Carroll, who was going over some details on technique. That's nothing new for Carroll, a former safety and defensive backs coach by trade who likes working closely with defensive backs, particularly ones who are new to his defense. 

For now, Tre Flowers is still working with the No. 1 defense at right cornerback, but as Dunbar gets up to speed, he is expected to compete with Flowers for that job.

3. Geno Smith throws a good deep ball too.

As is so often the case, one of the highlight's of the day was a Russell Wilson deep ball, a pass that hit DK Metcalf in stride for a big despite tight coverage from Pro-Bowl corner Shaquill Griffin, but Sunday's practice also showed that Wilson isn't the only quarterback with a big arm.

Geno Smith, who was Wilson's backup last season, completed a couple of very nice deep passes Sunday as well, including one to free-agent addition Phillip Dorsett II, who has been showing off his speed early in camp.

4. Opportunities for young defensive tackles.

Jarran Reed and Poona Ford, Seattle's two returning starters at defensive tackle, were both held out of Sunday's practice after leaving practice early on Friday. We'll wait to hear from Carroll before speculating on potential injuries, but the absence of Ford and Reed does present a good opportunity for a couple of second-year defensive tackles, Bryan Mone and Demarcus Christmas. 

Mone, who was the only undrafted rookie to make the 53-man roster out of camp last year, and Christmas, a sixth-round pick who missed last season with a back injury, will have every opportunity to earn significant roles in the defensive line rotations, particularly with Al Woods leaving in free agency, so getting first-team reps early in camp should only help their development.

5. Well read, Shaquem.

Shaquem Griffin carved out a role for himself late last seasons as a situational pass rusher, and he's definitely in the mix to stay in that rotation this year, but Seattle's depth at linebacker and the addition of Bruce Irvin, who like Griffin plays a hybrid strongside linebacker/defensive end role, means the third-year linebacker will have to prove himself all over again in camp. 

On Sunday, Griffin made the type of play that is likely to get noticed by coaches, coming off the edge on a zone-read play, properly reading Russell Wilson's fake to Chris Carson, while staying home to contain Wilson. With quarterbacks off limits to contact, Wilson was able to make a couple moves to get free, but in a live-game situation, the play was definitely a win for Griffin.