Caldwell has brought another new element to practices with two sets of 11-on-11 drills going on at the same time rather than just one.
Instead of having so many players standing around watching one group, the double drill allows more reserves to get extra reps that they wouldn't have gotten in the past.
Receiver Calvin Johnson said the team is responding to Caldwell's approach.
"He told us what he wanted, what he expected," Johnson said. "We're out here giving it to him every day. He told us if you come out here and bust our butts in practice, we won't be on the field that long. That's what we're doing, busting our butts."
--- Rookie kicker Nate Freese, a seventh-round draft pick, is off to a rough start in training camp.
His first attempt Wednesday night got blocked by Ndamukong Suh. Freese came back to make 43- and 48-yarders, but then missed another 48-yarder wide right at the end of practice.
Giorgio Tavecchio, in competition with Freese, made his 48-yard attempt at the end.
"We've just got to make sure we're consistent on all our kicks," Caldwell said. "That's an important part. We've got guys that are very capable."
--- George Johnson (6-foot-4, 263 pounds) has received some quality reps at defensive end with Ezekiel "Ziggy" Ansah currently out with a shoulder injury.
Johnson, who went undrafted in 2010 coming out of Rutgers, has played in a total of 11 games over the last four years with Tampa Bay and Minnesota.
"He's changed his body a tremendous amount since he's been in the league," Caldwell said. "He used to be a lot bigger, carried a bit more weight.
"He's got a gift, speed and quickness. He's another one of those guys that we're excited about having the opportunity to see how it goes here."
--- The Lions claimed receiver Quintin Payton off waivers from the Tampa Bay Buccaneers. Payton (6-4, 212 pounds) is an undrafted rookie from North Carolina State.