CINCINNATI -- Bengals quarterback Joe Burrow remains out indefinitely after undergoing an appendectomy at the beginning of training camp.

Bengals coach Zac Taylor said he doesn't have a timetable for Burrow's on-field return.

"I hate to put a timeline on it," Taylor said Friday. "But he's getting a lot of good mental work right now."

The third-year quarterback and top overall pick in the 2020 draft hasn't participated in any practices since the Bengals started training camp last week. But Burrow remains visible and active during the preparation for the upcoming season.

Taylor said Burrow is involved in team meetings, even leading some of them like he did before Friday's practice. When asked if Burrow could be used to signal playcalls like Arizona Cardinals quarterback Kyler Murray is doing during their respective camp, Taylor said that wasn't necessary.

"He's been plenty engaged," Taylor said. "I don't think we need that to stimulate him. He does a pretty good job of that."

Burrow has been outside with the team during two practices this week, observing the team's drills on a medical cart. He drove the medical cart across the field with the rest of the offense at the end of Thursday's practice as the unit participated in some light conditioning as penalty for losing a team drill to the defense.

Taylor said Burrow has been very visible to his teammates, even if he hasn't been able to be fully engaged during training camp.

"We get excited to see him around," Taylor said. "He's our quarterback."