Antonio Pierce likes what he sees from the Ravens and expects Baltimore to stay undefeated with a win over the Raiders. (0:22)

OWINGS MILLS, Md. -- Some teammates describe safety Eric Weddle as edgy. Others call him a little weird. He is known to pull out a big brush and start combing his bushy beard during meetings.

What everyone agrees on is how Weddle has taken hold of the Baltimore Ravens' defense in three games and is a major reason why it's ranked No. 2 in the NFL.

Weddle has been the teacher and leader that this defense has desperately needed recently. This shows in how Ravens defenders are seemingly always in the right position to make plays this season.

New Ravens safety Eric Weddle, right, has served as a teacher and mentor to his teammates since coming aboard. Photo by Patrick Smith/Getty Images

"We joke around and say that is 'Coach Weddle,'" linebacker Zachary Orr said. "He is just constantly reminding us, little tips [such as], 'Get your depth here; this is what they like to do.' In the heat of battle, it is great to have someone like that who can remind you of little tips that the offense likes to do."

Since Ed Reed left after the 2012 Super Bowl season, the biggest problem for the Ravens defense has been giving up big plays. Time and time again, Baltimore's inability to stop offenses from going over the top of it stemmed from a lack of communication. There was a breakdown that allowed a receiver to get behind the secondary.

From the first day Weddle stepped onto the practice field, you could hear him yelling out instructions to teammates. He told them where to properly line up and prepared them for what was about to come. In training camp, defensive coordinator Dean Pees (who used to coach for the Patriots) said Weddle has had a Junior Seau-like influence on the team.

Weddle believes he caught his teammates off guard by how much he was willing to teach them.

“They just weren't really used to a guy not only loving the game, but willing to help and willing to be there for them," Weddle said. "I don't know how it has been in the past, but everywhere I have been, I try to lead more for the guys that I have played with than for myself. I want them to know as much as I know myself. At the end of the day, if my teammates don't know what is going on and can't play at a high level, we are not going to be the best we can be."

Weddle isn't just a mentor or an aging veteran who is only here to delve out wisdom. He's been the NFL's top safety this season, according to Pro Football Focus.

He is constantly making his presence known, whether it's getting a hand on a pass or making an open-field tackle. His four passes defensed leads Baltimore and his 14 tackles rank fourth on the team. Weddle's Week 2 interception in Cleveland 2 helped spur the comeback, and his pass breakup at the 1-yard line last Sunday saved a touchdown.

Even though he has played only briefly with the Ravens, it feels like he's been a part of the team for a long time.

"The word that comes to mind is 'Raven.' He has kind of that Raven persona," linebacker Terrell Suggs said. "You have to like a guy like that who has a little bit more to him and is a little edgy."

The Ravens coveted Weddle in free agency. Baltimore gave him $13 million in guaranteed money, which is only the second time the Ravens have doled out more than $4 million in guaranteed money from the Ravens since 2010. (Elvis Dumervil was the other.)

Weddle also showed how much he wanted to come to Baltimore. He turned down more money to sign with the Ravens after being pursued by three other teams, including Sunday's opponent, the Oakland Raiders.

“Eric is a very smart player. He's a very experienced player, and he's a very dedicated," coach John Harbaugh said. "I don't want to leave out that he's a very talented player. He can make plays on the ball, he can move, and he can do all of those things just as well. He adds in every aspect. He's made us better.”