The 2016 NBA Draft is full of question marks and things don't always work out as planned for college underclassmen who declare for the draft.

Many players are testing the waters and have until May 25 -- 10 days after the NBA Draft Combine -- to return to college as long as they don't hire an agent.

Here are 20 players who would be better served by returning to school and the reasons why they should stay in school.

Isaiah Briscoe | Kentucky | PG/SG | Fr.

The New Jersey native did a tremendous job at changing his body when he arrived in Lexington and that allowed him to become a terrific perimeter defender as a freshman. Now it’s time for Briscoe to improve his offense. The 6-3 guard shot just 5-of-37 from 3-point range last season and needs to prove he can score in ways other than simply bullying opponents in the paint. Briscoe's return to Lexington would provide John Calipari with a strong veteran presence in the backcourt that would anchor the Wildcats’ talented first-year class of De’Aaron Fox, Malik Monk, Wenyen Gabriel, Sacha Killeya-Jones, and Bam Adebayo with some much needed veteran experience.

Marcus Lee | Kentucky | PF | Jr.

A former McDonald’s All-American, Lee finally saw regular minutes for the first time his college career last season and did a very solid job inside for the Wildcats. But that doesn’t mean he’s even close to being ready to play in the NBA. The 6-9, 224 pound jumping jack averaged 6.4 points, 6.0 rebounds, and 1.6 blocks in 21.8 minutes for Kentucky with most of his points coming directly around the rim. Lee should return to school and attempt to bulk up and refine his offense in hopes of providing the Wildcats with another seasoned frontcourt player in their rotation.

Troy Williams | Indiana | SF | Jr.

Williams is an NBA level athlete, but that doesn’t mean he’s a lock to be a first-round pick. The 6-7 forward has only made a combined 38 3-point shots during his three years with the Hoosiers and needs to recalibrate his offensive game if he wants to have an immediate impact at the next level. Williams also needs to improve his ball security as last season he tallied 70 assists to 93 turnovers. With another year under Tom Crean, “inspector gadget” will be a potential top-10 pick in 2017 and he’ll also give Indiana a legitimate chance to win a second consecutive Big Ten regular season title.

Trevon Bluiett | Xavier | SF | Soph.

The Musketeers are a top-five team nationally if Blueitt returns next season and he’s also likely to get a bigger piece of the pie at Xavier with the departures of both James Farr and Jalen Reynolds. The 6-6 forward excelled as an undersized power forward last season, averaging 15.1 points and 6.1 rebounds while shooting 39.8 percent from 3-point range in what was a banner season for the Musketeers. Expect those averages to increase by 20 to 25 percent in 2016-17 if he comes back to Xavier.

Nigel Hayes | Wisconsin | PF | Jr.

Hayes struggled at times as a primary option for the Badgers after being an ancillary piece the past two seasons behind both Sam Dekker and Frank Kaminsky. He’d be best served to return for his senior season after shooting career lows in both field goal percentage (36.8) and 3-point percentage (29.3). Should Hayes go back to Wisconsin, the Badgers would be the clear favorite in the Big Ten next year. And it may not be close.

V.J. Beachem | Notre Dame | SF | Jr.

Beachem is a nice player and a deadly shooter, but he’s simply not ready to play in the NBA. The 6-8 wing would struggle to guard his position and needs to get better off the bounce. 88 of Beachem’s 159 made field goals last season were 3-point shots. This guy needs to be stronger off the dribble and improve his ability to defend if he wants to have a real chance at the next level.

Julian Jacobs | USC | PG | Jr.

A freak athlete, the 6-4 Jacobs was one of the most improved players in the Pac-12 last season and one of the main reasons why the Trojans played in the NCAA Tournament. But that doesn’t mean he should bypass his senior year of college. Jacobs’ play making skills are still a work in progress despite his solid 2:1 assist-to-turnover ratio and he also needs to continue to get better from long range. The bouncy junior only made 15 3-point shots last season and that number needs to go up if he wants to be a point guard in the NBA.

Jaron Blossomgame | Clemson | SF | Jr.

The 6-7 forward isn’t on any draft boards despite having a strong hand (18.7 points, 6.7 rebounds) in leading to the Tigers to 10 ACC wins without a true home court advantage. Blossomgame would be considered one of the best players in the best conference in college basketball next season and that would coincide with Brad Brownell’s team breaking through and reaching the NCAA Tournament. If this guy returns to school next season then Clemson is a lock to hear its name called on Selection Sunday.

Malik Pope | San Diego State | SF | Soph.

This 6-10 wing has been an intriguing prospect for years, but his production level has never matched his talent. Pope only averaged 7.3 points and 5.0 rebounds last season as a sophomore and would be best served if he returned to Southern California for his junior year.

Abdul-Malik Abu | NC State | PF | Soph.

Abu has already proven that he’s a very good college player and he’ll be even better next season playing with freshman point guard Dennis Smith. The first-year floor general should get Abu more scoring opportunities at the rim and advance his overall numbers (12.9 points, 8.8 rebounds) considerably. This decision is a no brainer for Abu.

Justin Jackson | North Carolina | SF | Soph.

Jackson quietly averaged 12.8 points in the Tar Heels’ run to the national title game and could be this team’s go-to player if he returned to Chapel Hill for his junior season. Roy Williams is losing both Marcus Paige and Brice Johnson to graduation and he needs a new alpha dog to emerge. Jackson could play his way up the draft boards thanks to the athleticism he’ll show in individual workouts, but he’s a potential lottery pick in 2017 if he spends next year as the Tar Heels’ go-to guy.

Malachi Richardson | Syracuse | SG | Fr.

This 6-6 wing was a key cog in the Orange’s run to the Final Four as a freshman and could be Syracuse’s primary offensive option as a sophomore if returns to campus. With Franklin Howard and incoming freshman Tyus Battle set to round out Jim Boeheim’s perimeter next season, Richardson should emerge as the Orange’s alpha dog as long as he returns to school. The New Jersey native is far from being a first-round lock and could use an extra year of seasoning at the collegiate level.

Josh Hart | Villanova | SG | Jr.

Hart was the Wildcats’ leading scorer and second leading rebounder during their national title run and while he may be able to play his way into the latter part of the first round, he’d be best served by returning to the Main Line. Oklahoma’s Buddy Hield was projected as a late first-round pick 12 months ago and he likely worked his way into the lottery thanks to a terrific senior season. The same thing could happen for Hart if he returns to the Main Line in 2016-17.

Isaiah Whitehead | Seton Hall | SG | Soph.

This Coney Island native has dreams of being a first-round pick and that’s far from a lock in 2016. Whitehead played as well as any perimeter player in college basketball over the last month of the season and would make the Pirates a potential top-15 team if he returns to South Orange for his junior season. Another year under Kevin Willard would mean another year of tutelage in regards to the nuances of his game and right now that’s not something Whitehead can pass up to be drafted somewhere in terms of the mid-to-late second round.

Maurice Watson | Creighton | PG | Jr.

Watson had a great season (14.1 points, 6.5 assists, 3.4 rebounds) after transferring from Boston University, but this declaration is more about testing the waters than actually staying in the 2016 NBA Draft. Watson needs to return to school and help lead the Bluejays back to the NCAA Tournament for the first time since 2014.

Caleb Swanigan | Purdue | PF | Fr.

This brute big man led the Boilers in rebounding as a freshman (8.3) and would be more of a focal point for Purdue next season following the departure of A.J. Hammons. Swanigan can score, pass, and do work on the boards. He’d be best served by being featured for a year in college before heading to the NBA.

Tyler Dorsey | Oregon | SG | Fr.

The 6-4 Dorsey (13.4 points, 4.3 rebounds) was an elite freshman in a year in which the Ducks reached the Elite Eight for the first time since 2007. If he came back to school next season Dorsey would be a an All-Pac-12 first team caliber player as a sophomore. Another reason why Dorsey could use another year of college? A free attempt to refine his play making skills (71 assists, 69 turnovers), which need to be better if he's going to eventually play point guard in the NBA.

Dillon Brooks | Oregon | SF/PF | So.

Brooks was a mismatch nightmare this past season thanks to his ability to exploit traditional big men who played power forward. If he wants to play in the NBA, he needs to tighten his handle and be more capable of scoring the basketball against players who fit his body type and mold. If Brooks returns to Oregon, the Ducks could again be to the team to beat in the Pac-12.

Rodney Purvis | UConn | SG | Jr.

The Huskies will be more of a “downhill” team next season with Jalen Adams and freshman Alterique Gilbert pairing together in the backcourt and that would really benefit Purvis. The 6-5 pitbull is always better when he plays on a decline and could have his best college season yet if went back to Storrs.

Amida Brimah | UConn | C | Jr.

This 7-footer was a revelation when the Huskies won the national title in 2014, but he's struggled to turn a corner over the past two seasons. Brimah has battled injuries and also the ability to stay on the court for long stretches due to foul trouble. An elite rim protector, Brimah has never averaged less than 2.3 blocks during his college career. Post defense is a major work in progress for this Ghana native who always shows flashes of promise without the element of consistency. There's a much better chance of that happening next year at UConn than in the NBA or the D-League.

Indiana's Troy Williams and Kentucky's Marcus Lee would be wise to return for another year of college. (USATSI)
Indiana's Troy Williams and Kentucky's Marcus Lee would be wise to return for another year of college. (USATSI)