Rosen is still adjusting to his new surroundings after the Dolphins acquired him from the Arizona Cardinals in April.
"I think he's made some improvement, really across the board. There's things that a lot of people don't see. Better footwork, mechanics in the pocket, decision-making. A lot of times people, all they see is the touchdown pass; they don't see the checkdown that's a positive play for the team. I think he's improved in those areas and I think those are the little things that go a long way at that position."
While he spoke highly of Rosen, Flores gave the impression Tuesday that Ryan Fitzpatrick was higher on the depth chart.
Though some quarterbacks thrive in their rookie seasons, Rosen's 2018 performance showed he may make a more gradual adjustment to the NFL.
To some extent, the Cardinals set Rosen up to fail. He wasn't ready to be the starter and faced constant pressure because of an offensive line that ranked 26th in adjusted sack rate, per Football Outsiders.
The writing was on the wall regarding his future when Arizona, with the No. 1 overall pick in the 2019 draft, set its sights on Kyler Murray.
Flores previously avoided classifying the Dolphins as a rebuilding team, but Miami is likely to be among the league's worst squads in 2019. By rolling with Fitzpatrick for Week 1 and beyond, Flores would sidestep the mistake Arizona made.
Rosen turned only 22 in February. Especially since they're embracing more of a long-term view, the Dolphins can afford to be patient with his development.
There will come a time when Miami needs to hand Rosen the keys to the offense and let him sink or swim. For now, his strides on the practice field can qualify as progress.