Rookie offensive lineman Brian Allen isn't satisfied. 

He's nearly through his first professional training camp, has clearly made strides, and has even received some extended practice reps. But as he's leaving the field following Monday's session — during which he served as the first-team center with John Sullivan receiving a veteran rest day — Allen is frustrated with himself. He hasn't been as consistent as he feels he needs to be. 

"I'd say a little bit more up and down than I'd like," Allen says of how his first camp has gone. "I have good practices and then do something rookie-esque, and kind of ride that wave for a little. And then have a good day and then have one of those days. So, really, kind of average right now. 

"But, definitely getting better, understanding our system a little bit more every day, and, really, just trying to learn that as much as I can."

As a rookie, the learning process is to be expected. It's part of why Los Angeles drafted young linemen like Allen, Joe Noteboom, and Jamil Demby this offseason in the first place — they have a great opportunity to grow behind what was zone of the NFL's most effective offense lines in 2017. 

Being a rookie, Allen acknowledges there's plenty he doesn't know simply because he's inexperienced. And sometimes that can lead to rookie mistakes. But that knowledge doesn't lower the young center's expectations for himself. 

"At this level," he says, "you can't have that if you want to stick around or continue to get better. So is it normal? Yeah. If you want to be one of the good ones, can't have it. So, keep trying to eliminate that stuff and keep picking these older guys' brains and get better."

Not that most young players don't demand excellence from themselves, but it's striking how candid Allen is in discussing his performance. He's hard on himself, and he says it's just the way he's always been. 

"It's just me. I don't want to just be a guy — I want to be pretty good at this," Allen said. "That's not going to happen with behavior like that, stuff like that. So, just coming out and, like I said, gotta get rid of that, and keep getting better from that. And if that stuff continues, that takes away from time to get better. And if I repeat those mistakes, I'm not really getting better. So just try to learn from everything and not mess everything up twice. But I'm hard on myself, going to be hard on myself. And if I'm not, I shouldn't be here." 

So, these "rookie mistakes." Most times it's hard to determine exactly what's going with the offensive line at the line of scrimmage — particularly when you don't know the assignments. But there was a time or two in Monday's practice when Allen's shotgun snaps to quarterback Jared Goff were low, disrupting the rhythm and timing of the play. 

Nevertheless, Goff had complimentary words for the rookie center following the session. 

"He did a good job," Goff said. "There were definitely some things as a rookie that you go through, just letting the game slow down a little bit. But he stepped in there, I thought he did a really good job and started to settle in towards the end of practice."

While Allen appreciates the benefits of reps when the veterans receive rest days, he wants to earn more. 

"I'd like to be getting in on the days that they are there, but I'll take the ones that I can get," Allen said. "Any time that you get to work with those guys, not only is it pretty cool to be out there with the starters — guys you look up to, guys you grow up [watching] — I think Whit's been playing in the NFL since I was in elementary school. So just to be out there and playing with guys of that caliber is surreal. And any chance you get to go with the ones is special. So you've got to take advantage of it." 

That's exactly what Allen will look to do as training camp winds down and the preseason continued. After playing 61 percent of the snaps last week against Baltimore, he's likely to receive another extended look against Oakland on Saturday. And in the aftermath, he'll likely be just as hard on himself as he works to improve. 

"If I want to keep stacking blocks, I've got to minimize the rookie stuff. And as we've gone on it's been slimming down," Allen said. The game was alright. I've got to build off that, play with better technique and [get rid of] some nerves and stuff like that. But just keep getting better."