JUST LAST WEEK BRUCE ARENA ACKNOWLEDGED that the central midfield combination of Jermaine Jones and Michael Bradley was not sufficient and that he was going to look at other possibilities. That pairing has long been a source of frustration for American fans and now it looks like the team might move on from a combination that has struggled since Bob Bradley first introduced it in 2011.

“It certainly didn't look like anything special," Arena told reporters, "and as we move forward we continue to look at different possibilities."

The good news for Arena is that there are plenty of players knocking at the door. The bad news: there is not much of an opportunity to run through the different combinations before June World Cup qualifiers against Trinidad & Tobago and Mexico. 

Right now at the attacking midfield positon (also referred to as the No. 10 ), the box-to-box position (No. 8), and the defensive midfield position (No. 6) nothing seems set in stone.

Christian Pulisic could lay claim to the No. 10 role but it is not yet settled if Arena will use the Pennsylvania teenager in that position or out on the wing. In fact, Arena may not use anybody in the No. 10 spot.

That said, the way Arena deploys Pulisic will have a huge impact on what the central midfield landscape looks like. Looking at current crop of American forwards, Arena has to be leanding toward a  two-forward formation—an approach that has been successful for the national team over the years and what Arena used in the two most recent qualifiers.

If the coach does go with a two-forward formation, he can go with a straight 4-4-2 with Pulisic on the wing with more traditional box-to-box central midfielders in the middle.

However, Arena could also start Pulisic centrally behind two forwards with the fullbacks providing width in the attack. This would be a 4-4-2 diamond with midfielders like Darlington Nagbe and Kellyn Acosta pinched in (the injured Sebastian Lletget also seems to fit this role). Or it could look like a 4-3-1-2 with a trio of box-to-box or defensive midfielders behind Pulisic providing a more conservative balance.

Based on what Arena has said, who he has played so far, and the form of the current players, this is my best guess as to where things are right now in central midfield and where they’re going—noting that several players can play more than one position.

The Attacking midfielders

1. Christian Pulisic
2. Sacha Kljestan
3. Sebastian Lletget
4. Benny Feilhaber
5. Emerson Hyndman
6. Clint Dempsey

Behind Pulisic, this position is pretty unclear at the moment. Sebastian Lletget came out strong in his World Cup qualifying debut last month but he suffered a long-term injury that raises questions about when, and if, he will return to the national team.

Kljestan has played all over the midfield during his career. At Anderlecht, he was a holding midfielder in a 4-2-3-1 but he has excelled at the No. 10 for the Red Bulls, creating countless chances for a strong offensive team. That said, Kljestan is 31-years-old and only made the March qualifying roster as an injury replacement.

Similary, Benny Feilhaber similarly remains in the picture but Arena neglected to call in the Sporting Kansas City veteran after seeing Feilhaber during January camp. The last option listed above is for Clint Dempsey to shift back to the No. 10 and play behind the forwards. This is far from ideal but not a bad emergency option.

The Box-to-Box midfielders

1. Michael Bradley
2. Sebastian Lletget
3. Jermaine Jones
4. Kellyn Acosta
5. Darlington Nagbe
6. Sacha Kljestan
7. Emerson Hyndman
8. Cristian Roldan
9. Danny Williams
10. Alfredo Morales
11. Lynden Gooch

At the 2014 World Cup, Jermaine Jones and Michael Bradley were both given ample freedom playing box-to-box roles while Kyle Beckerman (or Geoff Cameron in the final game against Belgium) sat behind them and in front of the defense.

With Beckerman seemingly no longer in the picture, Arena has attempted to use Bradley in a more defensive position with Jones playing further up the field. That combination has not worked out. Arena also tried Lletget in a more box-to-box role in January camp but again, his injury puts those plans on hold. Nagbe is an option here as well and he could thrive in a skinny diamond but Nagbe seems to be at his best out wide.

This is where Kellyn Acosta has a clear opening. If Arena wants to go younger and perhaps push past aging options like Jones and Kljestan, Acosta is one of the most in-form players in the player pool right now. The young FC Dallas product has taken his game to another level and looks to be international quality.

Seattle's Cristian Roldan and Rangers’ Emerson Hyndman are both impressing at their clubs and look to be ready for a Gold Cup look. Lynden Gooch could get a shot too although the Sunderland product has seen his first-team minutes fall off in recent months.

Danny Williams and Alfredo Morales remain in the picture—and Williams' stock could rise quickly if Reading earns promotion to the Premier League. The problem for both players, however, is that neither looked completely in-synch with the U.S. national team under Jurgen Klinsmann. Will Arena want to attempt to revisit unsuccessful Klinsmann projects? Perhaps, and Williams is likely a much better bet than Morales.

Defensive midfielders 

1. Michael Bradley
2. Dax McCarty
3. Geoff Cameron
4. Kellyn Acosta
5. Jermaine Jones
6. Perry Kitchen

Bradley tends to enjoy his freedom and the ability to get into the attack, but he can also be a good defensive midfielder. He has the motor to cover a lot of ground, has impressive defensive skills, and certainly possesses the desire required for the job.

Geoff Cameron has been playing this role at Stoke and should remain an option at defensive midfield for the national team. Still, it's hard to see Arena taking him off the backline, where he has performed well on the international stage.

McCarty is an interesting case. He is not flashy but he is tactically disciplined and could serve the same sort of role Beckerman played in his prime. In that sense, McCarty is the only pure defensive midfielder on this list and it would not be surprising to see him succeed in that role.

Potential new combinations

So beyond Bradley-Jones and with Lletget on the shelf for several months, Arena can try out several options over the upcoming months. With the above-mentioned players, there are a lot of different combinations to consider. But which ones are we most likely to see in the June qualifiers or the Gold Cup in July?

Bradley and Acosta: Bradley and Acosta have never been paired in the midfield together and that is looking more likely as the MLS season progresses. Acosta has been in top form and he plays a disciplined role at Dallas alongside Carlos Gruezo. It is easy to see Bradley playing well with Acosta either in a 4-2-3-1 or a 4-4-2 with Pulisic on the wings.

McCarty and Bradley: This pairing would also be interesting either behind Pulisic or in a formation where McCarty sits deep and gives Bradley a more free-ranging role. Bradley has produced some solid games with Beckerman (and without Jones) so this combo could recreate that type of environment. Note: Bradley would need to be in top form in this setup. If he is not, it would create a huge hole in the link between offense and defense.

Acosta-Hyndman-Pulisic or Acosta-Roldan-Hyndman: While a massive overhaul and a completely experimental roster for the Gold Cup is both unlikely and unnecessary, Emerson Hyndman and Cristian Roldan are two potential names that could be given a big opportunity. Even though the quality in Scotland has declined, Hyndman is playing so well that it is not out of the question that he emerges as Pulisic’s back-up or Arena even finds a way to play Pulisic and Hyndman together.

A central midfield that consists of Acosta behind Hyndman and Pulisic could be a real glimpse of the national team future. If Pulisic is given a break for the Gold Cup, then a trio of either Bradley or Acosta behind Hymdman and Roldan also could be successful. It is very possible that Bradley is included with the mix of younger players, but these four are clearly part of the next generation trying to push forward.

Williams-Bradley: Should Arena want to explore more experienced but underutilized options, Bradley and Danny Williams could also receive strong consideration. Williams has had a very good season for Reading and cannot be discounted.

Tactically, Williams has been in the attacking midfield part of a 4-3-3 formation and that has been different than his more defensive-oriented positions in previous seasons. Williams is talented but he has often suffered for both club and country because of his versatility—he has never really settled into a specific role. Could he form a partnership with Bradley? Would one play behind the other? If so, which one? Potentially, any of these could work, or not. 

The future of Jones and Bradley

But what to do about Jermaine Jones? He’s not out of the picture by any means. But at age 35, he is not the player he once was. Arena needs to look at other options. He can’t go to the World Cup with Jones as a lock starter—which could result in other candidates being unprepared. Is Jones willing to ride the bench while Arena explores other options? Will he fade gradually as Father Time catches up with him?

Michael Bradley is considered by many to be an automatic starter, but should he be? Arena might want to sit both Bradley and Jones on the bench while other options are evaluated. Still, Bradley is on the tail end of his prime and has a ton of experience: two World Cups, Serie A, the Bundesliga, the Eredivisie, MLS as a teenager, and the national team captaincy. He has had some off games recently but it would hardly be surprising to see him return to form under a fresh system devised by Arena.

Either way, Arena has his work cut out for him as he considers his options in the central midfield. However it plays out, it seems likely that Christian Pulisic will be his key consideration—similar to how Arena built his team around Landon Donovan for the 2002 World Cup. If the coach gets it right—like he did 15 years ago—the U.S. could make some real noise in Russia.