Todd McShay analyzes the top three picks in his latest NFL mock draft and explains why Carson Wentz could be the first quarterback selected. (1:40)

Assuming the New Orleans Saints' medical staff signs off on Notre Dame linebacker Jaylon Smith, then ESPN analyst Todd McShay's latest mock draft would be fantastic for the defense-starved team.

McShay has Smith falling to the Saints with the 47th pick in Round 2 because of concerns over possible nerve damage in Smith's surgically-repaired left knee.

Before Smith underwent his medical tests at the NFL scouting combine in February, it seemed like he might not even fall to the Saints at No. 12 in Round 1.

But when it comes to Smith, mock drafts are even more of a guessing game than usual. If he was healthy, the Butkus Award winner might even be in the mix to be drafted No. 1 overall. ESPN analyst Mel Kiper said Smith might be the best talent in the draft after racking up more than 100 tackles in each of the past two years.

2016 NFL DRAFT Round 1: April 28, 8 p.m. ET

Rds. 2-3: April 29, 7 p.m. ET

Rds. 4-7: April 30, noon ET

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• Mel Kiper Jr.: 'Grade A' Mock »

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• Mel Kiper Jr.'s Big Board »

• Top prospects by position »

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However, Smith tore his ACL and LCL during the Irish's bowl game, so he might not be ready to play at the start of the 2016 season -- if not longer. Concerns about possible nerve damage led sources from at least three teams to tell ESPN that they don't intend to draft Smith.

Next month's medical re-checks at the combine could go a long way toward determining Smith's status.

The 6-foot-2, 223-pounder might end up being worth the risk for the Saints -- especially in Round 2 -- if the medical people are confident he can eventually get back to 100 percent.

Yes, the Saints need help for their defense right away. But they also need to rebuild that unit for the long haul and can wait a year for a talent this special.

Meanwhile, McShay has Louisville defensive tackle Sheldon Rankins going to New Orleans with the 12th pick in Round 1.

Rankins (6-1, 299) has been one of the most popular mock draft choices to the Saints for the past two months -- including Kiper's last two mocks. McShay switched to Rankins from his previous choice of Alabama DT A'Shawn Robinson, who has also been a popular choice for the defense-needy Saints.

Rankins has an impressive combination of power and athleticism and the versatility to be an asset as both a run defender and pass rusher from the three-technique position. He had 14 sacks and 26.5 tackles-for-loss over his final two seasons.

Sean Payton listed pass-rusher and three-technique defensive tackle as the Saints' top two "musts" this week and said they might address both in the draft. They could address both at once with a player like Rankins.