Joe Robbins/Getty Images

Quarterbacks and defensive linemen have been at the forefront of the 2019 NFL draft discussion since the end of the college football season.

A majority of the top six selections on April 25 in Nashville are expected to be either quarterbacks, edge-rushers or interior linemen based off the quality of talent that is available.

The Arizona Cardinals' decision with the No. 1 pick will go a long way in determining the draft order, but if they take Heisman Trophy winner Kyler Murray, the picks should fall into order nicely for most of the teams beneath them.

The San Francisco 49ers, New York Jets, Oakland Raiders and Tampa Bay Buccaneers could all use defensive upgrades, while the New York Giants have been linked with a quarterback for most of the draft process.

2019 NFL 1st-Round Mock Draft

1. Arizona Cardinals: Kyler Murray, QB, Oklahoma

2. San Francisco 49ers: Nick Bosa, EDGE, Ohio State

3. New York Jets: Quinnen Williams, DT, Alabama

4. Oakland Raiders: Josh Allen, EDGE, Kentucky 

5. Tampa Bay Buccaneers: Devin White, LB, LSU 

6. New York Giants: Dwayne Haskins, QB, Ohio State

7. Jacksonville Jaguars: Jawaan Taylor, OT, Florida

8. Detroit Lions: Montez Sweat, EDGE, Mississippi State

9. Buffalo Bills: Jonah Williams, OT, Alabama

10. Denver Broncos: Drew Lock, QB, Missouri

11. Cincinnati Bengals: Cody Ford, OG, Oklahoma

12. Green Bay Packers: Rashan Gary, EDGE, Michigan 

13. Miami Dolphins: Ed Oliver, DT, Houston

14. Atlanta Falcons: Brian Burns, EDGE, Florida State 

15. Washington Redskins: D.K. Metcalf, WR, Ole Miss

16. Carolina Panthers: Greedy Williams, CB, LSU 

17. New York Giants (from Cleveland): Andre Dillard, OT, Washington State

18. Minnesota Vikings: Clelin Ferrell, EDGE, Clemson 

19. Tennessee Titans: T.J. Hockenson, TE, Iowa

20. Pittsburgh Steelers: Byron Murphy, CB, Washington

21. Seattle Seahawks: Deandre Baker, CB, Georgia

22. Baltimore Ravens: Marquise Brown, WR, Oklahoma

23. Houston Texans: Greg Little, OT, Ole Miss

24. Oakland Raiders (from Chicago): Noah Fant, TE, Iowa

25. Philadelphia Eagles: Josh Jacobs, RB, Alabama

26. Indianapolis Colts: Christian Wilkins, DT, Clemson

27. Oakland Raiders (from Dallas): Dalton Risner, OT, Kansas State

28. Los Angeles Chargers: Dexter Lawrence, DT, Clemson

29. Kansas City Chiefs: Garrett Bradbury, C, NC State

30. Green Bay Packers (from New Orleans): Rock Ya-Sin, CB, Temple

31. Los Angeles Rams: Jaylon Ferguson, EDGE, Louisiana Tech

32. New England Patriots: Daniel Jones, QB, Duke

Marquee Prospects

Quinnen Williams

By all accounts, Alabama defensive tackle Quinnen Williams has done everything in his power to be a top-three pick when April 25 rolls around.

NFL Network's Ian Rapaport reported Wednesday that Williams was visiting with the New York Giants and also that the defensive lineman has met with most teams in the top 10 and every franchise selecting in the top five.

NFL Network's Peter Schrager added some detail as to why Williams is impressing so many teams in the buildup to the draft:

There is an outside chance Williams lands at No. 1 to the Arizona Cardinals, but that is dependent on what happens with Murray.

If he doesn't go to the NFC West with the Cardinals, he could set up shop in that division with the San Francisco 49ers, who have a difficult decision to make at No. 2.

The 49ers have to select between Williams, Nick Bosa and Josh Allen, all of whom could make an immediate impact on the defensive interior.

Since San Francisco has a good amount of pass-rushing depth, the 49ers would be going after who they think is the best player available at No. 2.

The New York Jets could be a perfect fit for Williams at No. 3 because of a handful of factors.

Not only would Williams be the best player on the board if Arizona and San Francisco were to pass on him, but he would also fill a void on the interior.

ESPN.com's Rich Cimini noted the Jets could be face a decision between Allen and Williams at No. 3 after the defensive tackle visited the facility Tuesday:

Since the Jets shored up their depth at linebacker by signing C.J. Mosley in free agency, it would make more sense to solidify another area of the defense with Williams instead of piling on depth at a single position by taking Allen.

Prediction: No. 3 pick.

Dwayne Haskins

Once Murray presumably goes off the board in the top five, Ohio State quarterback Dwayne Haskins is expected to be the most coveted player at his position.

For most of the pre-draft process, Haskins has been linked with the New York Giants at No. 6.

Paul Vernon/Associated Press

The Giants could opt to take Haskins and have Eli Manning groom him, which is something the Ohio State product would be more than willing to have happen, as he stated on Rapoport's Rap Sheet and Friends podcast (h/t NFL.com's Adam Maya).

"Eli Manning is a legend," Haskins said. "I grew up watching Eli, and I'd have no problem sitting behind him and learning from him, like how I did with J.T. [Barrett] at Ohio State."

Selecting a successor to Manning is important for the Giants as they enter a bit of a rebuilding stage following the Odell Beckham trade.

But there is a possibility the Giants wait until the 17th pick to take a quarterback, which could be Duke's Daniel Jones at that juncture.

If that is the case, the Giants would have likely taken a defensive player at No. 6 and allowed Haskins to drop a few spots, with the Denver Broncos, Cincinnati Bengals and Miami Dolphins hoping he falls to them.

While that scenario could play out, it would be wise of the Giants to not pass up on a quarterback in the top 10 for the second straight year and secure the services of Haskins, who could learn under Manning for at least a season.

Prediction: No. 6 pick.

Follow Joe on Twitter, @JTansey90.