In an offseason marked by widespread change, the center of midfield has largely been left unaltered. Stalwarts Vincent Nogueira and Brian Carroll are back for their third and sixth seasons, respectively. Mid-season acquisition Warren Creavalle has been re-signed, and it looks like Maurice Edu will finally be able to play exclusively in the middle of the park, his natural position. The rebirth of Bethlehem Steel also brings some new faces into the mix, as those players must be considered when talking about the Union's depth.

Today, we're going to talk about the two more defensive central midfielders. Attacking midfield depth will be addressed in a later article.

As we've already seen so far this preseason, there can be a lot of fluidity in the central midfield. Vincent Nogueira, who has played as the Union's ball-moving No. 8 over the past two years, has made a few appearances as a No. 6, where he was asked to sit deep and break up play in midfield. Maurice Edu will likely be Nogueira's more defensive partner this season, even though his preferred role is more similar to Nogueira's. While this depth chart will be broken up, it's worth mentioning that that type of overlap exists throughout the roster.

No. 6s

1. Maurice Edu

Edu has started both of the last two seasons in midfield, but injuries and a lack of depth at center back forced him onto the back line. He'll start in the midfield once again this year, and thanks to the Union's defensive additions in the offseason, it looks like he'll be able to stay there.

Though he is a natural center midfielder, Edu's previous stints in central midfield haven't been so pleasant. As we've seen, Edu is fond of carrying the ball up the field, linking attack to defense. There's nothing inherently wrong with that, but his resistance to adapt to other roles has proven to be an issue. As a defensive midfielder and even as a center back, Edu's more attack-minded tendencies tended to overtake whatever tactical instruction he had been given.

At one point last season, Vincent Nogueira said that he preferred playing next to Brian Carroll. At 34, Brian Carroll is not a better player than Maurice Edu, but he does have a deep understanding of his role. Edu will need to learn how to play alongside and defer to Vincent Nogueira, or else the Union will have a very tough decision to make.

2. Brian Carroll

You pretty much know what you're going to get out of Carroll at this point. He's a no-frills defensive midfielder who will sit deep, win the ball, and get out of the way. His athleticism and his passing are what prevent him from being a starter, but his breadth and depth of intelligence make him a great locker room guy and a serviceable back-up.

3. Warren Creavalle

Creavalle, similar to Carroll, is a simple defensive option in central midfield. At 25, he's more athletic and less experienced, but he has gotten a fair number of games during his pro career. He can also play as more of a No. 8 and he's capable of filling in at right back. Barring major injuries, we likely won't see too much of him this year.

4. Derrick Jones

The Ghanaian made history when he became Bethlehem Steel FC's first-ever player back in December. Jones, an alumnus of the Union's academy, had trained extensively with the first team prior to signing with Bethlehem. He was once thought to be an attacking midfielder, but he recently told USLsoccer.com that defensive midfield is his "favorite position right now."

Considering how long he's been around the first team, it's only a matter of time until Jones joins the Union.

5. James Chambers

Chambers, 29, has more than a decade of experience in Ireland's top flight. He'll be a good influence on guys like Jones and Akinyode, and he figures to start in midfield for Bethlehem. Though he's 5th on the depth chart, his international status limits his upward mobility.

6. Boluwatife Akinyode

Bolu Akinyode is a 21-year-old defensive midfielder who most recently played for New York Red Bulls II, the USL affiliate of the MLS team with the same name. Born in Nigeria, Akinyode came over to America as a boy (You can read more about his story here). His dual citizenship will make it easier for him to sign with the first team if that opportunity ever presents itself.

No. 8s

1. Vincent Nogueira

Over the past two years, Nogueira has stood out in a position that often gets overlooked. The long-time Sochaux captain is worthy of all the cliches typically assigned to excellent passers. He's a metronome who is always two steps ahead of everyone else; he's playing chess while everyone else is playing checkers. All kidding aside, Nogueira is fantastic in possession. His ability to make the right pass is unparalleled and it can't be overvalued. The Union are a markedly better team when he is on the field.

Nogueira's only trouble is staying on the field. He's made 28 and 22 starts in 2014 and 2015, respectively. Nagging injuries have plagued him over the years, and the Union will certainly hope that he can stay healthy in 2016.

2. Roland Alberg

Two weeks ago, I wrote that Roland Alberg would likely find a starting spot on the wings. Today, I have absolutely no clue what to think. In the preseason games he's played, Alberg has started as the No. 8 alongside Nogueira, who assumed a more defensive role. When Maurice Edu returns from injury, Alberg will have to find somewhere else to play. He could displace either Chris Pontius or Sebastien Le Toux on the wings--likely the latter--or he could play under CJ Sapong and push Tranquillo Barnetta out wide.

Wherever Curtin settles on starting him, it's possible that Alberg slides back into central midfield if (when) Edu or Nogueira gets injured. The Union are stacked on the wing, but they aren't as strong in the middle. Alberg is a better option than Carroll, even if his fit with Nogueira might be a bit more forced.

3. Leo Fernandes

Fernandes has played both on the wing and in central midfield so far this preseason. He played out wide when he was on loan with the New York Cosmos last season, and he does look more comfortable there. But the Union's wing depth is the best it's ever been, and Fernandes's quickest path to playing time might come through the center of midfield.