Timmy Jernigan broke into the Eagles' backfield and did a fly by on their quarterback, yelling as he ran past to make sure everybody knew it would have been a sack in live football.

Then Jernigan went back to his side of the line of scrimmage and started doing the "Bernie Dance," shirt pulled up to show off his belly.

"Just having fun, man," Jernigan said with a big laugh. "You've got to have fun out there. That's part of the game."

The Ravens' newest starter in their defensive front seven is back from a foot injury and it's clear that he's having a lot of fun and his opponents are not.

"[Have] you guys been watching in practice? You haven't seen him?" outside linebacker Elvis Dumervil said to reporters. "The guy – he's in the backfield the whole time. He plays with a passion. He wants it."

Jernigan went down with a foot injury on Aug. 8. He returned to individual drills on Saturday, Aug. 15, and has been at full speed for the two joint practices in Philadelphia. He feels he's had his best practices yet in Philly.

The man tasked with stepping into the shoes vacated by Pro Bowler Haloti Ngata will be making his preseason debut this Saturday at Lincoln Financial Field.

It was perfect timing, Jernigan said, because he was very much looking forward to going against another team. Jernigan even talked to some of his former FSU teammates about Eagles Head Coach Chip Kelly, who coached against them while Kelly was at Oregon.

"They told me his offense was pretty tricky, so I looked forward to going in there against him," Jernigan said. "I remember last year when we went against the 49ers, I remember how fun that was. So I was really looking forward to coming here."

Last week, Defensive Coordinator Dean Pees said Jernigan's biggest issue is that he hasn't been able to stay on the field all the time. It's not his fault, Pees said, but it's hard to get a true evaluation if a player's not on the field day after day.

Jernigan missed four games last season due to a knee injury. He's dealt with different bumps and bruises throughout his young career.

But when he's on the field, the 2014 second-round pick is eye-catching. He's adept at shooting gaps, which disrupts the timing in the opposing running games and creates pressure on the quarterback in pass situations.

"Timmy is the kind of guy that plays at the point of attack, but he can also step in and run behind two blocks and make the play, like he did yesterday a couple times," Head Coach John Harbaugh said. "You just never can be sure where he's going to be exactly."

In order to step in for Ngata this year, Jernigan will need to be an every-down player. He did so when Ngata was suspended last season and Jernigan started three games, making 10 tackles and two sacks.

Last season, he was the NFL's sixth-best run stopping defensive end and had the league's second-best pass rush productivity, only trailing Houston Defensive Player of the Year J.J. Watt, according to Pro Football Focus.

"I expect to be dominant every down on the field, whether it's first down or fourth, whether it's goal line or a passing situation," Jernigan said. "You can't really be one-sided in this league. You can, but it's really no fun. I love the game of football and I want to be on the field every play I can be and dominate."