The Lions filled a few of their critical needs in the NFL draft, but ESPN analyst Mel Kiper said their success in 2013 will be largely determined by first-round pick Ziggy Ansah.

"Is this going to propel them back into the playoffs?" Kiper said during a conference call Monday. "It depends upon how quickly Ziggy Ansah develops into a premier pass rusher."

Ansah began playing football in 2010 and only had nine starts at BYU — all last season — so the fifth overall pick will be a bit of a project in the NFL.

Kiper said he doesn't expect Ansah "to take the NFL by storm" this season, but thinks the defensive end could be productive as a rookie.

"Fair expectations would be for him to be a force off the edge," Kiper said. "It doesn't mean he has to have 10 sacks, but just make progress. Come in, start early on this year and at least hold your own, and then develop as the season goes along."

Overall, Kiper said the Lions did well in the draft and gave them a B grade on ESPN.com.

One player the Lions may have considered at No. 5 instead of Ansah was Alabama cornerback Dee Milliner, who went ninth to the Jets.

Instead, the Lions grabbed Mississippi State cornerback Darius Slay in the second round, and although Kiper said he's not as fundamentally sound as Milliner, Slay has upside because of his speed (4.36-second 40-yard dash).

The Lions also drafted South Carolina defensive end Devin Taylor in the fourth round.

"You protect your back end by getting a pass rush, so (the Lions) get the pass rush first, then you get the back end second," Kiper said. "If they can motivate Taylor and coach up Taylor, they may have something there at least in the rotation at defensive end.