FOXBOROUGH, Mass. -- Patriots rookies were on the field for a one-hour practice Friday morning as the team's rookie minicamp kicked off, and Bill Belichick was a head coach on the move as he closely monitored different aspects of the session.
Few can get inside Belichick's head to know what he's thinking. An easier task is to follow him across the two practice fields behind Gillette Stadium and report what he's viewing.
The session started with 26 rookies (12 draft picks, eight free agents, five tryouts, one veteran punter) completing stretching and agility drills before breaking down into specific positions. Belichick went with the offensive linemen on the far side of the field, twirling his whistle as line coach Dante Scarnecchia drilled center/guard Ted Larsen (sixth round), tackle Thomas Welch (seventh round) and tackle John Wise (rookie free agent) as they worked on the heavy bag.
Belichick, wearing shorts, a visor and blue hoodie, seemed especially focused on the linemen's feet, while also keeping his eyes on their hand placement on the bag.
For many of the rookies, taking the field for the first time as a pro heightens their nerves. Having Belichick specifically watching them would seem to add to the pressure they are facing.
"I saw him over there," acknowledged Welch, a towering 6-foot-7, 310-pound prospect from Vanderbilt. "But the key is that you can't get off your routine, because we're going to be playing in this stadium and there are going to be thousands of people watching. I was just trying to listen to Coach Scarnecchia and do what he was asking me to do."
After a short period watching the offensive linemen, Belichick moved to the next station, where defensive line coach Pepper Johnson had seventh-round draft picks Brandon Deaderick and Kade Weston and free agent Kyle Love working on the heavy bag.
Much like he did with the offensive linemen, Belichick seemed to be looking closely at footwork and hand-placement techniques.
After those drills ended, Belichick chatted briefly with director of college scouting Jon Robinson, and then football research director Ernie Adams. The early focus on linemen seemed to be a case of Belichick wearing his scouting hat, looking closer at prospects from an evaluation standpoint, and then sharing some of his observations with those from his inner scouting circle.
The practice continued with the offense working on one field and the defense on the other, with Belichick watching the offense, which was decisively directed by quarterbacks coach Bill O'Brien. The drill was basic, with quarterback Zac Robinson (seventh round) getting to the line of scrimmage, identifying the middle linebacker, and then snapping the ball with the goal of everyone being on the same page.
Soon enough, the focus turned to the kicking game.
Linebackers and tight ends worked with special teams coach Scott O'Brien on the blocking sled on one corner of the far field, while receivers and defensive backs were drilled by coaching assistant Brian Flores on the far corner of the other field. Belichick watched O'Brien's group from afar.
The next part of practice was devoted to a punt-team drill, and as that unfolded, Belichick spoke with director of player personnel Nick Caserio, which again seemed to highlight the on-field evaluations that were taking place throughout the session.
After the special-teams focus, the offense split to one field and the defense to the other, with Belichick staying with the defense and watching from multiple angles as his assistant coaches ran the drills.
The practice ended soon after, and when Belichick met with media members, he called the opening of rookie minicamp "exciting", while adding that it's a reminder of how far the team's veteran players have come. He said the practice was focused on basics like receiving the play call, getting into the huddle and lining up correctly.
"I thought the group had good energy," Belichick told reporters, before adding that the goal of the entire minicamp is to get to know the prospects and have them become familiar with the team's X's and O's and overall program.
Friday's morning practice was the first step in the process.
Tracing Belichick's movements across the practice fields -- from offense, to defense, to special teams -- it was clear that even the smallest detail was a big deal.
Mike Reiss covers the Patriots for ESPNBoston.com. Follow him on Twitter.