Chychrun, named to the Ontario Hockey League All-Rookie Team in 2014-15, is No. 4 on NHL Central Scouting's final ranking of North American skaters. Sergachev, named the 2015-16 OHL Most Outstanding Defenseman, is No. 8.

Based on size and maturity, many believe Jakob Chychrun (6-foot-2, 200 pounds) of Sarnia and Mikhail Sergachev (6-2, 221) of Windsor are the two capable of earning NHL roster spots for the 2016-17 season.

"There's no predicting the order of the top four or five [defensemen] of this draft class," NHL Director of Central Scouting Dan Marr said. "They're all good. They're all different in their own way. We kept Chychrun at the top of our list; he's a real deal as far as we're concerned. It's going to be up to the individual team, who they want at that position. They're all quality players, they're all going to be in the National Hockey League sooner rather than later. You can talk to five or six different teams and they'll all tell you who they would have No. 1.

"It's a very good corps of [defensemen], and they're all going to be a top-four on their NHL team."

The battle for No. 1 among defensemen in the 2016 draft might come down to Chychrun and Olli Juolevi (6-2, 188) of London. Scouts believe Juolevi, No. 5 on Central Scouting's final ranking, could turn out to be the best of the bunch.

"Olli is a puck-moving defenseman and his style of play will definitely translate well to the NHL level," London coach Dale Hunter said. "NHL teams look for a puck-mover who can hit that first pass."

NHL scouts will have their work cut out in determining which defenseman to choose when the 2016 draft is held at First Niagara Center in Buffalo on June 24-25.

Here are NHL.com's top 10 defensemen eligible for the 2016 NHL Draft:

1. Jakob Chychrun, Sarnia (OHL): The left-shot defender is considered an excellent skater with high-end hockey sense and passing ability. He had 11 goals, eight power-play goals, 49 points and a plus-23 rating in 62 games, and had four points in seven games for Canada at the 2016 IIHF World Under-18 Championship.

2. Olli Juolevi, London (OHL): Juolevi had nine points, all assists, in seven games to help Finland win the gold medal at the 2016 IIHF World Junior Championship. The left-shot defender exhibits excellent poise and composure with the puck, and good instincts without the puck. He had nine goals, 42 points and a plus-38 rating in 57 regular-season games, and seven points in four games to help London win the Memorial Cup.

3. Mikhail Sergachev, Windsor (OHL): Sergachev, the youngest player to be named the best defenseman in the OHL, led the League's defensemen with 17 goals and was third with 57 points. A solid two-way defenseman with deceptive speed and quickness, he also had 31 power-play points and a plus-15 rating in 67 games.

4. Charles McAvoy, Boston University (H-EAST): The 6-foot, 199-pound right-shot defender was named to the Hockey East All-Rookie Team after he had three goals and 25 points in 37 games. McAvoy can process the game quickly in transition and contribute in all situations. He has a pro-game mentality at this stage in his development. McAvoy also helped the United States win bronze at the 2016 WJC.

5. Jake Bean, Calgary (WHL): Bean led Western Hockey League defensemen with 24 goals, and had 64 points in 68 games in his second full WHL season. A native of Calgary, Bean (6-1, 173) has a good shot and can defend well using his mobility and smarts.

6. Dante Fabbro, Penticton (BCHL): Fabbro (6-0, 192) led British Columbia Hockey League defensemen with 67 points in 45 games and was named the top defenseman in the League. He also had 14 goals, and led BCHL defensemen with four game-winning goals and was second with eight power-play goals. The right-shot defender is committed to Boston University for 2016-17. Scouts liked how he usually was in position to break up most plays and force opponents wide.

7. Dennis Cholowski, Chilliwack (BCHL): The 6-1, 177-pound left-shot defender played in the BCHL last season as a 16-year-old but was more impactful this season with 12 goals and 40 points in 50 games. He finished the season strong with seven goals and 14 points in his final 15 games. Cholowski can think and process the game exceptionally well.

8. Logan Stanley, Windsor (OHL): The 6-foot-7, 224-pound left-shot defender, who partnered with Sergachev this season, has enough mobility to handle speed and defend well against most rushes. He is difficult to beat 1-on-1 and has an edge to his game. Stanley had five goals, 17 points and 103 penalty minutes in 64 games.

9. Lucas Johansen, Kelowna (WHL): Johansen (6-1, 175), the brother of Nashville Predators center Ryan Johansen, offers a complete game and is smooth in transition. He doesn't do anything great but does a lot of things well and is considered as steady as they come. He had 10 goals, 49 points and 29 power-play points in 69 games.

10. Kale Clague, Brandon (WHL): A strong skater who can elude forecheck pressure and make a solid first pass off the transition, Clague (5-11, 184) had six goals, 43 points and a plus-25 rating in 71 games. Scouts like that he's a composed player who is capable of making good choices in pressure situations.