So what do the Ravens make of Carr's situation? Will he play or will he sit?
"For some reason, I won't believe it until I don't see him out there," Ravens safety Eric Weddle said. "I know what a competitor he is and he's a tough dude."
If there's anyone who has insight on Carr, it's his good friend Weddle. When Weddle saw Carr get injured in Week 4, he immediately texted the quarterback. They've been talking on and off throughout the week.
"I'll wait to fully commit," Weddle said. "I hope he's out there, quite honestly. If he's not, we'll plan accordingly."
Last Sunday, Carr suffered a transverse process fracture in his back. A day later, Raiders coach Jack Del Rio said Carr would be out at least two weeks and named backup EJ Manuel his starting quarterback.
The intrigue began Thursday, when Carr was a surprising participant in practice (albeit limited). He was again limited Friday.
The Ravens contend the Raiders offense doesn't change much whether it's Carr or Manuel. But there's big difference in level of quarterback play.
In beating Baltimore each of the past two seasons, Carr has completed nearly 68 percent of his throws for 550 yards. The two-time Pro Bowl quarterback has seven touchdowns and one interception for a 110.6 passer rating.
Manuel, meanwhile, hasn’t thrown a touchdown pass since midway through the 2015 season and hasn't won a start since Week 2 of the 2014 season. To put that in perspective, 70 different quarterbacks have won an NFL game during that time, according to ESPN Stats & Information.
"Derek Carr is Derek Carr," linebacker Terrell Suggs said. "He has definitely come into his own, but EJ Manuel has also been an NFL quarterback, and I think the last time we played him, they beat us. Say what you want, but they beat us. I think they are still going to try to win the game."
Manuel did beat the Ravens in 2013, although he did so in a remarkable way. In a 23-20 victory during his rookie season for the Buffalo Bills, Manuel recorded a 48.9 passer rating, the worst for a winning quarterback against Baltimore over the past 12 seasons.
He completed 10 of 22 passes for 167 yards, throwing one touchdown and two interceptions. The bigger factor in that game was Joe Flacco's career-worst five interceptions.
Four years later, the Ravens could face Manuel again ... unless Carr makes an unexpected return.
"You can see in the Denver game and in the preseason, [Manuel] runs the offense well," coach John Harbaugh said. "Other things that they may add with him we have to be prepared for, and that is a little bit of a guessing game. We have to figure out what those things are. The nice thing is we know enough about EJ Manuel as a quarterback to know what those things have been in the past, at least."