The Combine is upon us. Here are the three big questions I'll be keeping an eye on over the next six days – questions that will have significant bearing on the way the early parts of round one (and subsequently everything else) plays out:

1. Can Brandon Aubrey keep up on the turn?

Aubrey, who starred for Notre Dame this past season and the three before it, is the highest rated senior center back on the draft. Of the central defensive corps, only Generation adidas signee Miles Robinson is likely to hear his name called before Aubrey hears his.

There is one issue, and one issue alone that has certain coaches flummoxed about Aubrey, and it is his quickness in tight spaces, which translates directly to the ability to win 1-v-1 battles against forwards who can do stuff like this to you:

Aubrey needs to show well on agility and balance tests at the Combine, and then during the games he needs to win battles like the one you just watched above. Everybody knows he's got a great soccer brain and is pretty easily the best passer of the ball out of the back in the group of potential draftees, but if he tests and looks slow against these guys, he could see his stock drop precipitously.

If he doesn't? Then he could push his way into the top three, and be the next Matt Hedges.

Best guess: No. 6 to San Jose, but I wouldn't be shocked if Houston took him at No. 4

Hayes is everybody's second-favorite player in the draft because his skill, balance and agility in tight spots are all outstanding. I compared him to Darlington Nagbe (not quite that gifted, but still) in my Mock Draft, and I'll stand by it.

But he's nobody's favorite player in the draft because it's not clear what his outstanding skill is.

He's great at combining but doesn't have the vision to cut a game open with a touch

He's got speed to burn but almost never uses it to get behind the defense

He's a heady, high-IQ player who nonetheless was more of a sidekick than a centerpiece

I think things will shake out with him being asked to play as an inverted winger as a pro, and whoever drafts him will have to work on his off-the-ball movement in order to get him to understand he needs to threaten teams vertically. It can happen.

But on Day 1 we'll see him as a No. 6. Hayes played a bunch as a No. 8 at Wake Forest, so theoretically this isn't a huge stretch, and as I said he's a high-IQ player who understands the geometry of the game really well.

His lack of passing range, however, does present as an issue. I also wonder about his mentality. The great d-mids in MLS history – Ozzie Alonso, Shalrie Joseph, Chris Armas, Pablo Mastroeni and Dax McCarty are Nos. 1-through-5 on the list – all took every opportunity they could to inflict pain on opponents trying to play through the middle. German legend Andreas Möller once said of Armas that "no one with children should ever have to play against that man," and that pales in comparison to what players will say off the record about Ozzie, Dax and the rest of that lot.

We live in a more civilized age. But do you remember how the playoffs were officiated, and how dominant d-mids like Alonso, Michael Bradley and Marco Donadel were?

If you're the 6, you've got to do more than just shield the backline and win the ball back. You've got to scare the other team and make them miserable.

Best guess: No. 9 to Columbus as an inverted winger, though I could see him dropping all the way to No. 16

3. What does Adonijah Reid's scoring record really mean?

There is a lot of debate about the 17-year-old Canadian GA, who's part of the Canadian youth national team set-up. Everybody's seen him in those games with the Canucks, but not many have had a chance to watch him tearing up League1 Ontario, which is where Reid has played his club ball over the last few years.

Reid led that league – which in US terms would be considered "semi-pro," and comprises largely guys in in their early-to-mid 20s, many of whom are low-level washouts of European academies – in scoring as a 16-year-old, and started as a 15-year-old.

Is that equivalent to a 16-year-old leading the PDL in scoring? Or putting up big numbers for, say, a quality Division II college side like Southern Connecticut? Something greater, lesser, or in between those two options?

Really tough to say right now, though it's very much something that most GMs around the league want to see answered at least in part this week. If he shows out in the games by out-thinking and out-quicking the likes of Aubrey and Robinson, he could play his way into the top 10, or even higher.

If he's anonymous, he could drop out of the first round entirely.

Best guess: I don't think he falls past No. 21, but any team that needs a goalscoring winger could end up taking him before then