General managers don't know them, agents don't know them, players don't know them, writers don't know them . and fans don't know them.

What are "them"? Them are the rules governing baseball transactions, some of which are so convoluted that even when you think you know them, you don't.

All the ins and outs of transactions are covered, sometimes in excruciating detail, in a large loose-leaf binder titled, "The Official Professional Baseball Rules Book," something completely separate from the "Official Baseball Rules" (which cover only the game on the field).

Unfortunately, Major League Baseball doesn't make that loose-leaf binder available to the public. There's not really anything controversial or confidential in there, so maybe they just think we don't care and/or wouldn't understand the arcana contained within. And of course, MLB isn't famous for its public-relations acumen.

So we've consulted a variety of sources, including that elusive "Rules Book," and come up with a "Transactions Primer" which should answer at least some of your questions

Disabled Lists
There are two Disabled Lists, the 15-day and 60-day. The only real difference between them is that players on the 60-day DL -- sometimes called the Emergency DL -- don't count against a team's 40-man roster.

To be placed on either Disabled List, a player must be certified disabled by a doctor. That said, such certifications generally aren't particularly difficult to acquire.

Players can be disabled retroactively, up to a maximum of 10 days, beginning with the day after the last day on which they played.

A player on the 15-day Disabled List may be shifted to the 60-day DL at any time.

According to the Rules, players on a Disabled List "may be assigned to a Minor League Club for the purpose of injury rehabilitation for a maximum of 20 days in the case of non-pitchers and 30 days in the case of pitchers."

"Options"
After three years as a pro, a player must be protected on a team's 40-man roster, or he is eligible for the Rule 5 draft (more on that later). Once he's served those three years, and assuming he is added to the 40-man roster, his club then has what are called "options" on him.

When a player is on the 40-man roster but not on the 25-man Major League roster, he is on "optional assignment." One common misconception about the rules is that a player may only be "optioned out" three times. Actually, each player has three option years, and he can be sent up and down as many times as the club chooses within those three seasons.

When you hear that a player is "out of options," that means he's been on the 40-man roster during three different seasons, beginning with his fourth as a pro, and to be sent down again he'll have to clear waivers (more on those below).

Waivers
Waivers just might be the most complicated single aspect of the rules. In the rule book, a waiver is defined as "... a permission granted for certain assignments of player contracts or for the unconditional release of a Major League player ..."

If a player placed on Major League waivers is not claimed by another team during the three business days after waivers have been requested, then the players is said to have "cleared waivers," and the team has secured waivers for the remainder of the waiver period.

And what does that mean? Essentially, the team can do with the player's contract as it pleases. This generally means one of three things:

(1) They can send him to the minors (subject to his consent, if he's a "Veteran Player," more on that below).

(2) They can release him, which makes the player a free agent and thus available to sign with any team.

(3) They can trade him to another team, even if the so-called "trading deadline" has passed. Any trades made after July 31 may only involve players who have cleared waivers.

If a player doesn't clear waivers -- in other words, if he's claimed by another team or teams -- the club requesting waivers may withdraw the waiver request.

If the club doesn't withdraw the waiver request, the player's contract is assigned in the following manner:

(A) If only one claim is entered, the player's contract is assigned to that claiming club.

(B) If more than one club in the same league makes claims, the club currently lower in the standings gets the player.

(C) If clubs in both leagues claim the player, preference shall always go to the club in the same league as the club requesting waivers.

There are other, more esoteric rules involved here. For example, during the first 30 days of the season, the previous season's final standings are used to determine claim order, rather than the current standings.

Designated for Assignment
You'll sometimes read that a player has been "designated for assignment."

What does this mean? Essentially, it allows a club to open up a roster spot while it figures out what it's going to do with a player. As we'll see below, there are certain situations in which a team needs a player's permission to either trade him or send him to the minors. So rather than force the player to make a quick decision, the team can simply designate him for assignment while he decides.

More commonly, a player is designated for assignment so the club can open up his roster spot while they're waiting for him to clear waivers, which can take four or five days. Occasionally, a club will designate a player for assignment while they're trying to trade him. That's what happened to Hideo Nomo this past June.

"Called Up" vs. "Contract Purchased"
When a player is summoned from the minors to the majors, you'll see that he was either "called up" or his "contract was purchased." For most practical purposes, this really doesn't make much difference. If he's already on the 40-man roster, he's called up. If he's not on the 40-man roster, then his contract is purchased (for a nominal fee) from the minor-league team.

However, the player must be added to the 40-man roster when his contract is purchased, which often necessitates dropping another player from the 40-man roster, whether by release or trade.

"Veteran Players"
Any player who has been in the major leagues for five full seasons may not be assigned to a minor-league team without his written consent. This sometimes puts the team in a bad position, because a player with five years has every right to say, "I don't want to go to New Orleans. You can either release me and keep paying me, or keep me on the major league roster and keep paying. Your choice."

Also, a player with five years of service time who is traded in the middle of a multi-year contract may demand another trade prior to the start of the season following the one in which he was traded.

Any player with at least 10 years of Major League service, the last five of which have been with one Major League Club, may not be traded to another Major League Club without his written consent. This is commonly known as "the five-and-ten rule."

Player To Be Named Later
Quite often, you'll read that a player has been traded to another team for "a player to be named later."

There are two restrictions at work here. First, the transaction must be completed within six months. And second, the player named later can't have played in the same league as the team he's being traded to. That's why the player named later is almost always a minor leaguer.

And what if the teams can't agree on who that player will be? This happens rarely, but if no names are agreed upon initially, the clubs will agree on a price to paid in lieu of a player.

Sometimes, at the time of the deal the team receiving the player will provide the other club a list of minor leaguers, and later the club will have their pick of the players on that list. This list is negotiated at the time of the trade. In recent years, the Minnesota Twins lost Enrique Wilson this way. When it came time for Cleveland to make their choice, the Twins did what they could to "hide" Wilson, but the Indians found him anyway.

Finally, sometimes "Player to be named later" is used to trade players on the Disabled List, since it can be embarrassing for a club to trade for a guy who's on the DL.

The Rule 5 draft

First off, note that it's not the "Rule V Draft," but the Rule 5 draft. It's called the Rule 5 draft because the section of the Official Rules that covers the draft just happens to be Rule 5 in the book.

Eligibility: A player not on a team's Major League 40-man roster is eligible for the Rule 5 draft if: the player was 18 or younger when he first signed a pro contract and this is the fourth Rule 5 draft since he signed, OR if he was 19 or older when he first signed a pro contract and this is the third Rule 5 draft since he signed.

A player drafted onto a Major League roster in the Rule 5 draft must remain in the majors (on the 25-man active roster or the DL) for all of the subsequent season, or the drafting club must attempt to return him to his original club. However, since a returned Rule 5 player must first be placed on outright waivers, a third club could claim the player off waivers. But of course, that club would then also have to keep him in the majors all season, or offer him back to his original club.

Occasionally, the drafting club will work out a trade with the player's original team, allowing the drafting club to retain the player but send him to the minors.