There are indications, however, that head coach Marvin Lewis and his staff just might win their gamble on the former University of Virginia star.
"I think with just about every guy who has been taken [in the supplemental draft], there have been questions about their maturity, and that's the nature of the beast," allowed Bengals linebackers coach Ricky Hunley. "But with [Brooks], you can see a difference between a year ago, and where he is now. He gets it now. He understands this is his livelihood. And it's just a matter of time until the big lights go on for him."
Brooks, 23, is projected as the Bengals' starting middle linebacker for 2007, and coaches contend there are few players at his position with the kind of size-speed combination that he possesses. Although he slumped toward the end of the season, Brooks started five games as a rookie in 2006, registering 31 tackles, one sack and two passes defensed.
But even when Brooks participated in his first game of the year, in a backup role at Pittsburgh last Sept. 24, he guaranteed himself a résumé superior to that compiled by more than 25 percent of the players chosen before him in the 30 years of the supplemental draft. By starting two weeks later at Tampa Bay, a game in which he recorded 11 tackles, Brooks accomplished something that nearly half the supplemental picks couldn't.
Of the 34 prospects from the supplemental drafts between 1977 and 2005, nine never played even a single snap in a regular-season game and 16 never started. Only four ever made a Pro Bowl appearance. Just five carved out careers that included 100 or more games. The average career span for those 34 players is 44.1 regular-season appearances, the equivalent of less than three full seasons in the league. None has been elected to the Hall of Fame, although wide receiver Cris Carter, who ranks second in NFL history in career receptions, should become the first in the next few years.
A fourth-round choice of the Philadelphia Eagles in the 1987 supplemental draft, Carter is a rare success story from the summertime lottery.
Not even using a first-round choice in the supplemental draft -- and there have been eight of them, but none since 1992, when the New York Giants selected quarterback Dave Brown of Duke -- ensures positive results. For every Bernie Kosar (Cleveland, 1985) or Rob Moore (New York Jets, 1990), the quarterback and wide receiver, respectively, who had productive careers, there have been busts like linebacker Brian Bosworth (Seattle, 1987), quarterback Steve Walsh (Dallas, 1989) and quarterback Timm Rosenbach (Arizona, 1989).
There are 10 prospects in Thursday's supplemental draft. From that group, there probably are three viable candidates -- Georgia cornerback Paul Oliver, and offensive tackles Jared Gaither of Maryland and Nebraska's Chris Patrick -- to be selected. Any team that uses a pick in the supplemental draft must forfeit its corresponding choice in the April 2008 draft and be able to fit the player into its 2007 rookie pool allocation.
It is, for sure, a dicey proposition.
In fact, if the regular phase of the NFL draft is an inexact science, then the supplemental lottery is more like an already questionable experiment gone further awry. Teams roll the dice in the regular draft. In the supplemental draft, though, the process is more like a crapshoot, a game of blackjack and a spin of the roulette wheel, all rolled into one.
Consider the four players chosen in the supplemental drafts between 1999 and 2005. Safety J'Juan Cherry (New England, fourth round, 1999), never played a down in the NFL. Guard Milford Brown (Houston, sixth, 2002), has started 28 games in five seasons, but was released by Arizona last month. Tailback Tony Hollings (Houston, second, 2003), started just one game in three years for a Texans team desperate for running back help, averaged three yards per carry, scored no touchdowns and was out of the league in 2006. Defensive tackle Manny Wright (Miami, fifth, 2005), gained instant notoriety when he was filmed blubbering after coach Nick Saban reprimanded him during a 2005 training camp practice. His résumé consists of three games, four tackles and one sack. Wright sat out the entire 2006 season while battling depression, and has been released by two teams this spring.
Little wonder that, in the 30 years since the supplemental draft was instituted, there have been nine occasions in which not a single player was selected. In 11 other years, there was just one player picked. Only twice have more than two choices been exercised. The record for supplemental choices is five players, in 1989.
The most favored positions in supplemental draft history: running back (eight selections), defensive line (six), wide receiver (six) and quarterback (five).
Not since 1998, when the San Diego Chargers snatched defensive tackle Jamal Williams and the Green Bay Packers chose offensive guard Mike Wahle, both in the second round, has the supplemental draft produced any consistently productive players. Brooks has an opportunity to end the drought, but the Bengals' youngster will have to continue to make progress and stay out of the kind of trouble that regularly visited him during his college career.
Therein lies the basic problem in the supplemental draft. Most of the prospects are in the summertime draft because they are "special cases," players who have lost their academic eligibility, been kicked off a team or been involved in some manner of off-field indiscretion.
Typically, this year's pool of supplemental prospects includes all of the above.
Add to that the fact that players chosen in the supplemental draft are getting a late start, at least compared to those selected in the regular-phase draft, to their NFL careers. All the teams have finished their offseason programs, and players in the supplemental pool were not able to participate. Because the draft is held just a few weeks before training camps open around the league, supplemental draftees are playing catch-up.
Gaither, for instance, was not officially ruled academically ineligible by Maryland until last month, and had to work hard to get into some semblance of shape for his Monday audition in front of scouts from about half the league's franchises.
"It's an uphill battle from day one," acknowledged Brooks, who Cincinnati officials contend would eventually have been a first-round choice had he played out his eligibility in college. "You're fighting the odds all the way."
Len Pasquarelli is a senior writer with ESPN.com.