Carr injured his groin in the Raiders Week 15 loss to the Los Angeles Chargers and backup quarterback Marcus Mariota played well in three quarters and overtime in relief and was expected to start this week before Carr returned to practice.
"Derek practiced [Wednesday and Thursday] and so did Mariota," Gruden told reporters on Thursday. "We'll see what happens [Friday] in terms of which way we will go. We will have two quarterbacks prepared to play."
The Raiders host the Miami Dolphins on Saturday at Allegiant Stadium in Paradise, Nev. The Dolphins have allowed the fewest points per game in the NFL.
Gruden would not confirm that Carr will be active on Saturday, but said it was his "plan" to have the quarterback available to play.
"[Carr] has shown a lot of good things," Gruden said. "I'm not going to let the cat out of the bag. I'm going to make sure he's OK. I want to make sure he can do all the things he needs to do when going against a defense that blitzes almost every play."
Carr has completed 68.1% of his throws for 3,396 yards, 24 touchdowns and seven interceptions in 14 games this season.
The Raiders and Dolphins kick off at 8:15 p.m. EST Saturday.