​MIAMI GARDENS — Miami Dolphins cornerback JuJu Brents, arguably the team’s best defensive back, wasn’t spotted at Saturday’s practice at Hard Rock Stadium. It’s not known why Brents wasn’t at practice. Coach Jeff Hafley didn’t speak to the media Saturday. His next availability is Monday. The Dolphins are off on Sunday.Saturday’s practice, the ninth of traning camp, was the first practice in which the Dolphins tackled to the ground although they didn’t tackle to the ground during every 11-on-11 drill. For example, they didn’t tackle to the ground during the red zone 11-on-11 period. But they did tackle to the ground during the first 11-on-11 period.Brents’ absence meant the secondary was missing two starters because safety Dante Trader Jr. was absent. That offered opportunities for cornerbacks Ethan Bonner and rookie safety Michael Taaffe, among others. Newly-signed safety Tanner Wall got some looks with the third team in the red zone 11-on-11 period.Other notable Dolphins players that missed Saturday’s practice were guard/tackle Jamaree Salyer, wide receiver Kevin Coleman Jr., tight end Ben Sims, safety Lonnie Johnson Jr., and edge rusher Clelin Ferrell. Tight end Greg Dulcich was again wearing the red jersey, symbolic of no contact.Overall it was a spirited practice on a sunny day before an estimated crowd of 2,000, which is a decent training camp gathering.Tackling to the ground was brief, but enjoyableHafley said the Dolphins would tackle to the ground in training camp, and they did Saturday, much to the delight of players. No one got “lit up,” so to speak, meaning absorbing a big hit, but there was physical play, especially on the offensive and defensive lines.“We were just battling back to back, getting on each other, competing with each other, talking trash with each other, just, again, just having fun, ” edge rusher Chop Robinson said.A fight means an ejectionThe Dolphins haven’t had any fights in practice yet, partly because it leads to an automatic ejection. Players push their emotions just to the edge of fighting and then stop, by order of Hafley.Related Articles Dolphins camp: Jacob Rodriguez, Jonah Savaiinaea with strong stadium practice; plus stock up, stock down Dolphins cut struggling QB Mark Gronowski, add two newcomers This former Packers safety who’s familiar with Jeff Hafley may start for Dolphins Chris Perkins: Dolphins veteran LBs Dodson, Gay embrace training their replacements Dolphins camp: QBs throw four INTs; plus stock up, stock down “That’s what Haf wants us to do,” center Aaron Brewer said. “You throw a punch, you’re out of practice. So ain’t nobody tryin’ to get thrown out practice. So it’ll probably get intense, but ain’t nobody fightin’. You’ll probably get a push, but ain’t nobody throwing no punches. We’re tryin’ to practice.”Defensive draftees star in nice 11-on-11 defensive standThe red zone 11-on-1