FOXBORO — One heart-to-heart conversation with Bill Belichick was enough to rock Brandon Spikes’ football world.

The punishing Patriots linebacker found himself blown away last year by his coach’s challenge for self-improvement. Since then, Spikes has emerged as one of the NFL’s most intimidating enforcers, and he said yesterday he has barely reached his full potential.

Spikes, a 2010 second-round draft pick, was up and down through his first two seasons, but a conversation with Belichick really resonated during his breakout campaign last year. Belichick saw a freewheeling player who wasn’t spending enough time learning the defense as a whole; Spikes knew his individual assignments, but until he grasped the entire scheme, he’d be limiting his true ability.

“(Belichick) asked me one time, ‘Do you know how good you can be?’ ” Spikes said. “And I’m just running around here playing. It’s a game to me. It’s fun. I still love it. I look at it from a kid’s point of view. I’m out here playing ball and having fun. I don’t ever really think about it like that, but for him, coach has been doing it so long, has got big respect everywhere. To get that from him, I had to look in the mirror and ask myself, ‘Do I really want to take that step?’ ”

The conversations continued in the offseason, even when Spikes worked out in Florida instead of at Gillette Stadium. He understood the message, and he wanted to be more accountable to his teammates.

Through it all, Spikes has always genuinely cared more about victories than individual goals, which he doesn’t even set. The thought of increasing his defensive awareness was a bit intimidating, but the greater good was at stake.

Now, he has a tighter grasp of the safeties’ responsibilities behind him in pass coverage, as well as the gap assignments from the linemen in front.

“It’s different for me because I never, ever tried to do that,” Spikes said of learning the defense as a whole. “But as far as knowing where everyone is supposed to be, where they’re going to be, the pre-snap reads, the post-snap reads, it just helps me out. As far as reading schemes, I’m noticing formations and stuff like that. Bill is always on me, ‘Don’t get complacent. Do more and more, and the better you are, the better we are.’ I try to be accountable.”

Spikes knows where the message is coming from, too. Belichick has coached some remarkably successful linebackers, from Lawrence Taylor and Carl Banks as the defensive coordinator for the New York Giants to Tedy Bruschi and Mike Vrabel as coach of the Patriots. It was finally time for Spikes to step up.

“It used to go in one ear and out the other, but (Belichick) has definitely got the credibility,” Spikes said. “He’s coached the great ones. I’m in there with (position coach and former Giants linebacker) Pepper Johnson, and to hear how he approaches the game, it was just good for me. I feel like I’m in the perfect situation with guys like Bill and Pepper around.”

Spikes plays each down as if the next one isn’t guaranteed, and he believes the improvement in the classroom only enhances his physical presence. He had career highs last season with five forced fumbles, 92 tackles, one sack and seven pass defenses, and he merely referred to the campaign as a “steppingstone.”

The 25-year-old wants to shine on the field for those before him, for someone like Johnson who continuously lights a fire in Spikes’ eyes, and for the jewelry that can be won through a collective mission that ends with a Super Bowl title, not bought from a contract.

“That’s what separates you,” Spikes said. “At the end of the day, if you had a good career — yeah, yeah, yeah — but what do you have to show for it? All the work, all the hours that you put in, it only matters with those rings at the end of the day. Personally, I play for the rings. Don’t we all play for the rings? I don’t know. But I always play for the rings. That’s it.”

If a new dedication to classroom work is the means to that end, especially when the message comes from the man up top, Spikes is all for it.

“It’s time to take that step,” Spikes said. “Not be good. Try to be great.”