One of the most frenzied signing periods in the 42-year history of the baseball draft is about to take place over the next three days as big league teams have only until midnight ET on Wednesday evening to get players from this year’s draft under contract.

A uniform Aug. 15 signing date for all draft picks (except college seniors who have utilized all of their college eligibility) was instituted as part of a new Collective Bargaining Agreement between Major League Baseball and the MLB Players Association last fall. Previously, the deadline for players attending four-year colleges was the day they set foot in their first class in the fall; for players attending junior college under the since-abolished draft-and-follow rule, it was a week prior to the following year’s draft.

It is anticipated that upwards of 70 or 80 players could be signed in the final 72 hours before the deadline, including a number of first-round picks as well as players who could be paid bonuses significantly above the slot amounts recommended by the commissioner’s office.

The list of unsigned picks on the eve of the signing deadline includes 12 first-rounders (the Braves reduced the number to an even dozen by announcing the signing first-rounder Jason Heyward, the 14^th overall pick, on Sunday), including the top three selections in this year’s draft: No. 1 pick David Price (Devil Rays), No. 2 pick Mike Moustakas (Royals) and No. 3 pick Josh Vitters (Cubs).

There are 40 unsigned players overall in the top five rounds and 65 in the top 10 rounds. Several more prominent players drafted after the 10^th round are also expected to sign.

Major League Baseball will stick rigidly to the new signing deadline and has advised clubs that they must submit written verification to the commissioner’s office by either FAX or e-mail to make a deal official. The FAX or e-mail must contain all material terms and special covenants of the contract, including signing bonus, salary and, if applicable, the College Scholarship Plan and Incentive Bonus Plan. MLB has made it clear to clubs that a contract may not be contingent on an event (such as a player passing a physical) that occurs after midnight on Aug. 15.

If a team does not sign a player by the new deadline, it is precluded from doing so and the player becomes ineligible to sign. The lone exceptions are players that were not drafted in June or college seniors who have exhausted their college eligibility. In such cases, an undrafted player may remain eligible until he attends his first college class; college seniors may be signed at any time prior to the closed period prior to the 2008 draft.

To date, major league teams have stuck steadfastly by the commisssioner’s office’s guidelines on signing bonuses that strongly encouraged teams to roll back signing bonuses 10 percent from the bonus slots that were established in 2006. With one or two minor exceptions, teams have toed the line.

But all that is expected to change in the final hours leading up to the draft as contracts are officially filed with Major League Baseball and announcements on the actual signings of many “unsigned players” will be made public. There are a number of players who have reportedly agreed to deals above slot money, but those deals have not been reported to date because clubs have been reluctant to be the first to incur the wrath of the commisioner’s office, which has been on a mission for six years to scale back runaway inflation on signing bonuses—particularly in the first round.

“There’s a chance that all hell will break loose on Wednesday,” an American League scouting director said. “It’s going to be very interesting how all this plays out.”

It is anticipated that as soon as the first contract that is significantly above slot money reaches the commissioner’s office that a flood of contracts will be announced shortly thereafter.

Much interest will focus on Price, the first overall selection. His signing was not expected to be contentious all along and little or no rhetoric has come from either the Devil Rays or from Price’s agent, Bo McKinnis, since he was drafted June 7. The estimated slot amount for the first pick this year is $3.6 million, but it is anticipated that Price will receive substantially more than that figure—possibly in the form of a major league contract, which will enable the Devil Rays to spread out Price’s compensation over several years.

Vitters’ signing with the Cubs with the third overall pick is expected to be a formality, as are most others in the first round. But things are not as certain with Moustakas and the Royals with the No. 2 selection.Kansas City is not expected to go above slot (reportedly $3.15 million) to sign Moustakas, but the California high school infielder is being advised by agent Scott Boras, and Boras has rarely complied with signing his clients for slot money.

Of particular interest over the next few days will be an anticipated wave of signings announced by the Yankees and Red Sox.

To date, the Yankees have “officially signed” only four of their first 10 picks, but industry sources say the Yankees have agreed to terms with all of their unsigned selections in the top 10 rounds. The list includes first-rounder Andrew Brackman (another Boras client), who is expected to sign an above-slot bonus and immediately undergo Tommy John surgery to correct an elbow injury that caused him to slip in the draft to the end of the first round.

There are also reports that fourth-rounder Bradley Suttle, a third baseman from the University of Texas, and 10^th-rounder Carmen Angelini, a high school shortstop from Louisiana committed to Rice, will sign for bonuses that will be at or near seven figures.

The Red Sox, meanwhile, have “officially signed” only three of their first eight selections, and eight of their top 17. No club took more speculation picks (players that fell to lower rounds for signability reasons) in the draft than the Red Sox, and it is anticipated that they will sign a number of the selections to bonuses significantly above slot amounts. Among the players they are reported to have targeted for above-slot bonuses whose signings will be announced before the deadline are supplemental first-rounder Ryan Dent, fifth-rounder Will Middlebrooks, sixth-rounder Anthony Rizzo, seventh-rounder David Mailman, 13^th rounder Justin Grimm, 15^th-rounder Scott Green and 27^th-rounder Yasmani Grandal. All are high-profile high school selections with the exception of Green, a University of Kentucky righthander.

New York and Boston , in particular, have shown a reluctance to abide by the commissioner’s office’s recommendation on bonus slotting more than any clubs in recent drafts, ostensibly because they contribute more money to baseball’s central fund through excessive revenue sharing. As a result, they have become more defiant and less willing to toe the line when being told how to allocate their resources on talent procurement—particularly as they have provided significant revenues for other clubs to sign their draft picks.

Among the more interesting players to watch before the Wednesday midnight deadline will be New Jersey high school righthander Rick Porcello, Detroit’s first-round draft pick; University of Texas outfielder Kyle Russell, St. Louis’ selection in the fourth round; and Massachusetts high school lefthander Jack McGeary, Washington’s selection in the sixth round.

Porcello was projected to go second overall to the Royals in the weeks leading up to the draft, but slid to 27^th overall when the Royals and other teams determined his asking price was excessive. There are reports the 6-foot-7 Porcello is seeking a monetary package approaching $10 million and will attend the University of North Carolina if the Tigers do not meet his price.

Porcello is one of 12 prominent draft picks represented in this draft by Boras , who is notorious for making 11^th-hour deals under deadline pressure. Eleven of Boras ’ 12 selections have yet to sign.

Russell, who led the nation with 28 homers in the spring as a college sophomore, is reportedly asking for $1.5 million and would return to Texas if the Cardinals do not meet his bonus demands.

McGeary was targeted as a potential first-round pick much of the spring, but teams became reluctant to meet his bonus demands when he did not perform consistently like a first-round talent and he was passed over. The Nationals eventually selected him with the 190^th pick. There are reports they will make a last-ditch effort to sign him for a bonus in excess of $2 million while also enabling him to complete the bulk of his educational commitment to Stanford before becoming a full-time player in the Nationals system.

All in all, it could lead to three of the most fascinating days in draft history.