Defensive lineman Ndamukong Suh helped the Detroit Lions finish second in overall defense (300.9), first in rush defense (69.3 yards allowed per game) and eighth in sacks (42.0) last season due to his unique ability as both a stout run defender and disruptive pass-rusher. He finished 2014 with 53 tackles and 8.5 sacks. Unfortunately for the Lions, Suh now plays for the Miami Dolphins.

Detroit lost both Suh and Nick Fairley (who never really lived up to his first-round hype) to free agency this offseason and brought in Haloti Ngata and Tyrunn Walker to replace them. Will the new duo be able to help keep Detroit's defensive line as an area of strength?

"Help? Perhaps. Completely make up for? Not a chance," ESPN's Rob Demovsky wrote. "With apologies to Clay Matthews, Suh was the NFC North's most dominant defensive player. The Lions controlled games at the line of scrimmage in large part because of Suh. He was equally disruptive against the run and the pass. Because of the attention opposing teams had to pay Suh, he made players like Fairley, Jason Jones and Ziggy Ansah better. And say what you want about Suh and his antics, but he got in people's heads. This game isn't just physical; it's mental, too. Whether you liked the way he played or not, he used that to his advantage."

Ngata had a decent season as a space eating nose tackle in Baltimore's 3-4 defense last season, but he lacks the playmaking abilities of Suh as a 4-3 DT and is on the wrong side of 30. Walker, meanwhile, has collected just 28 total tackles and 3.5 sacks in 23 career games. He may only be 25 (three years younger than Suh) but he hasn't made a big impact in either of his two pro seasons.

The Lions still have a good defense with quality players at each level. But they are now missing their franchise defensive player from the last five years and replacing him won't be easy.