NAPA — Frank Gore nearly got himself sent to the bus early by Mike Singletary for going so hard.

The coach was only kidding — yet the last thing Singletary can afford is to have San Francisco’s star running back get unnecessarily banged up by bashing himself into the Oakland Raiders during an August practice.

Singletary asked Gore to tone down his intensity just a touch.

“Frank was outstanding. He was exceptional,” Singletary said. “If you got emotion, do it. What I was saying was I love the emotion. I love the enthusiasm. That’s the game. That’s passion. If I told him to stop doing that, he couldn’t. ... That’s just who Frank is. He’s a competitor. Everything he does, he does it with his heart. That really is the thing that sets him apart.”

Oakland and the 49ers kicked off two days of joint practices Tuesday — four sessions total — at the Raiders’ wine country training site. They then meet for an exhibition game Saturday night at Candlestick Park.

The teams liked doing this so much when they practiced together once last year they decided to do it again, a nice break for both clubs from the monotony of training camp. Not to mention a chance to see and hit another team.

Gore was in his element to say the least. And he certainly had some energy to release considering he was held out of the team’s first exhibition game, a 17-16 win over the Denver Broncos on Friday night, to keep him fresh. Singletary hasn’t decided whether Gore will play Saturday against the Raiders.

Under close watch by running backs coach Tom Rathman, a fired up Gore clobbered Oakland linebacker Ricky Brown and stood over him to make a point.

“Back, back, back!” Rathman hollered when Gore was slow to let the play end.

On his next turn, Gore and Thomas Howard went after it.

“Break,” barked Rathman. “When I say break, break!”

Later, Gore tried to jump in against undrafted rookie David Nixon. Rathman wouldn’t let that happen, knowing full well Gore might hurt the guy.

“Give me another back in here!” the coach yelled, pushing Gore away.

Gore, determined to replicate his career-best 2006 season this year, credits Rathman for helping him prepare for each play and treat training camp practices as if they were actual games.

“He wants us to be very aggressive,” Gore said. “He really helped me a lot when he came in by doing the small things, taking the angles. I try to do my best to do whatever he tells me to do because I see that he’s helping my game a whole lot. ... I feel that in this league anybody can run the ball. To be a complete back you have to catch and block. One of the toughest things is blocking. A lot of backs don’t like doing it, and it’s tough.”

In 11-on-11 work featuring the No. 1 offense and defense for both teams, Gore caught a pass from Alex Smith and was pushed out of bounds by Jon Alston. Alston — part of that earlier drill with Gore — patted Gore on the helmet good-naturedly.

Gore wasn’t the only one getting into it, either.

Raiders defensive tackle Gerard Warren made his presence known all morning.

“They need 8 for a field goal — 8 for a field goal!” he called out.

When Joe Nedney missed a 51-yard field goal off the left post moments later, Warren screamed, “No good, no good!”

Nedney then missed wide right on a 49-yarder.

“We win!” Warren proclaimed, signaling that the field goal didn’t make it.

Both sides were tame and kept things clean this time after tussling on several occasions during their 2008 joint practice.

“There’s no fighting,” Niners center Eric Heitmann said with a chuckle. “We came up here to work and really get a job done against another opponent. It’s always great to get a basis for how you’re progressing as a team when you go against someone else you haven’t seen every day in practice.”