The Bucks have a bright young nucleus led by one of the NBA's biggest stars, but they'll need to make some tweaks to become a contender. Roster flexibility will be key this summer.

​While the NBA playoffs are still going, the 2017 off–season is rapidly approaching for many teams with massive decisions to make.CBA expert Danny Lerouxbreaks down the major challenges and opportunities for theMilwaukee Bucks in The Crossover's NBA Summer Preview series.

After some surprising front-office turnover, which saw GM John Hammond leave for the same position in Orlando, the Bucks have a compelling set of challenges this summer. Most importantly, who is going to make them? As for the summer: The Bucks have a franchise centerpiece in Giannis Antetokounmpo and made the playoffs this season despite both Khris Middleton and Jabari Parker missing significant time, which bodes well for their future but also raises the stakes for possibly their final season with significant roster flexibility.

Here are three key storylines to watch for the Bucks this off-season:

• Greg Monroe: Like Pau Gasol in San Antonio, Monroe’s decision on a $17.9 million player option will significantly affect whether his team has usable cap space this summer. The talented center did not start a game this season and only averaged 22.5 minutes per contest—but don't let the numbers fool you, Monroe can still contribute to successful teams. While it appears unlikely he would be able to reach that $18 million bar on a new contract, adding years of security, the chance to pick his own team and the prospect of Thon Maker taking a much larger role next season could lead to an opt-out. While the Bucks could certainly use Monroe, clearing his salary would open the door for a slew of different opportunities depending on how much ownership is willing to spend long-term. If Monroe opts in, the Bucks could also look to trade him to a team looking for help on the interior that will not come with a multi-year contract like the high-end free agents or most of the other centers on the trade market. Depending on offers, that could open up a more useful talent distribution for next season if the Bucks are comfortable with Maker and John Henson as the key rotation pieces at center.

• Tony Snell: Trading Michael Carter-Williams for Snell was a massive success for Milwaukee, as the swingman started 86 games in the regular season and playoffs, averaged 8.5 points per game and shot 40.6% from three. While totally worth it, that production makes retaining the 25-year old restricted free agent a more expensive proposition. The Bucks have full Bird rights, so they can match any offer for Snell should they feel so inclined but keeping him at a high salary creates challenges down the line since Parker and Middleton are both in line for pay raises the next two off-seasons.

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• Jabari Parker extension: Halfway through the season, Parker was delivering on his promise by averaging 20.1 points and 6.2 rebounds per game as a part of Milwaukee’s dynamic front court. He tore his left ACL for the second time on Feb. 8 against Miami and will need a full year to recover. At the same time, Parker is eligible for an extension and it presents a challenge for both sides of the negotiation. The Bucks will not be able to see Parker at close to full strength before the extension window closes but he would still have enough time to make an impression and secure a lucrative offer sheet next summer. As such, the likelihood of a deal likely depends on how Parker and the Bucks feel about risk and how much he is willing to sacrifice in terms of peak value for the security of life-changing money before returning to the floor. While possible, a workable middle ground appears incredibly hard to find in this case.

Potential Free Agents: Tony Snell (Restricted), Greg Monroe ($17.9M Player Option), Jason Terry (Unrestricted), Michael Beasley (Unrestricted), Terrence Jones (Unrestricted), Gary Payton II (Non-Guaranteed) and Spencer Hawes ($6M Player Option)

Likely Summer of 2017 Cap Space: None

Realistic Maximum Summer of 2017 Cap Space (using $101M estimate): $10.2 million

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2017 Draft Assets: Own first (No. 17 overall) and second (No. 48) round picks

Potential Targets: Unless they move existing contracts, the Bucks will most likely need to make the most of the Non-Taxpayer Mid-Level exception (worth $8.4 million) and potentially either the Bi-Annual exception ($3.3 million) and/or a $5 million trade exception generated by moving Roy Hibbert at the February deadline. Milwaukee has an intriguing starting five with Antetokounmpo, Middleton, Malcolm Brogdon, Thon Maker and either Snell or Parker but could still use some quality complementary pieces. A talented wing like Thabo Sefolosha or Bojan Bogdanovic would be an intriguing addition but a defensive forward could make the largest difference if they retain Snell. James Johnson could guard either forward spot, allowing Antetokounmpo to focus more on help defense while also meshing with Parker when he returns. They could also look for lower cost replacements for Henson, Matthew Dellavedova or Mirza Teletovic if they can find an interested trade partner since none of them look to be long-term starters in Milwaukee considering their superior options under team control.

Pressure Scale: 6. Milwaukee already has its big pieces in place but this off-season provides their best chance to add in players who could be important parts in the next great Bucks team. Drafting well for the last few years and being pretty responsible with contracts has created a window where they can make a competitive team better and ideally add a contributor or two who can be on the team a few seasons from now. Parker’s potential extension adds some stress but that could transfer to 2018 if the two sides are simply too far apart. In normal circumstances, the Bucks’ off-season does not appear as challenging as other teams. However, their incredible ceiling as Antetokounmpo and their young core reach their prime makes each decision more significant since it affects a potential championship window.

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State of the Franchise: Finishing Touches. It looks like this is Milwaukee’s last strong shot to make fundamental changes to their team should they see a need. Parker’s significant cap hold for 2018-19 takes out a meaningful portion of their potential flexibility then while they will also be staring down pay jumps for Middleton and Brogdon a year later. That said, the Bucks have a piece of good fortune because the gap of about $20 million between the salary cap and the luxury tax means it should be possible to spend this summer without it becoming a massive burden in the near future unless Snell receives a richer offer sheet than expected. Whatever their options after Monroe’s decision, adding someone who fits well with their present and future would make a massive difference moving forward.