Brooks, signed as a free agent after being cut by the New Orleans Saints, got the majority of the work with the first-team offensive line, followed by Tuiasosopo and Walter.
Shell warned not to read too much into the pecking order.
"That's where we are today," Shell said. "The last (voluntary) camp it was different. It might be different next time. It could be different tomorrow. Nothing is set in stone."
Still, it was hard not to envision Brooks being the starter when the Raiders open Sept. 11 against the San Diego Chargers.
Evaluating quarterbacks based on non-contact mini-camps is tricky business, but Brooks showed a lively arm, good touch and the mobility that has been missing from Oakland's starting quarterback since Rich Gannon went out with a broken vertebra in 2003, never to return.
Tuiasosopo, after an aborted one-game tryout last season, threw the ball well but would appear to be a long shot. Walter, considered in some quarters to be the darkhorse candidate to start, threw the ball no better than Brooks and seemed to be in cement shoes by comparison to either of the first two quarterbacks.
Brooks said new teammates such as running back LaMont Jordan and wide receiver Randy Moss gave him a nice reception, with some calling him during a free agent visit in Tampa and beckoning him to Oakland.
"I'm off to a great start," Brooks said. "I'm just trying to get the playbook down and get them the ball the best way I can."
While conceding there had been no promises made, Brooks seemed confident the job would eventually be his.
"I bring a lot of energy. I bring a lot of mobility," Brooks said. "My leadership qualities carry over. I'm good with hands-on communication. My skills speak for themselves. The communication factor from player to player and player to coach is probably one of my best attributes. A team like this needs that."
Shell said he hoped to have a No. 1 quarterback in place heading into training camp, although the process could continue during camp if necessary.
"I want a guy who's going to get out there and make sure he protects the ball," Shell said. "I want a guy that is capable of being a leader. Some guys are great leaders. Jim Plunkett was not a great leader, per se, but he led by example in the way he played. I just want a guy to be under the center, pitch the ball, take care of it, and guys believe in him because he's doing the right things. If we do that, we'll be fine, whoever emerges."