By Ray Flowers, Special to SI.com, Head2Head.com

SABERMETRIC ALLEY

	The numbers prove further that Travis Hafner is a tough out. AP
	2006 BOP Leaders (min. 502 ABs and .250 average) Player BOP Travis Hafner 1.252 Ryan Howard 1.228 Albert Pujols 1.196 Manny Ramirez 1.183 David Ortiz 1.164 Jim Thome 1.147 Lance Berkman 1.142 Jason Giambi 1.091 Carlos Beltran 1.059 Miguel Cabrera 1.044

Truth be told, there are quite a few metrics that may not be classified as "new" but might be new to the general reader. The reason for this is basically we only know that which we are exposed to. Each week we will look at one sabermetric category that can be added to your "toolbox" of knowledge to help you capture your league's championship, through a simple explanation of what it measures.

BASE OUT PERCENTAGE

What is the most important element of baseball, the one thing that every team should protect at all costs? If you answered OUTS, then give yourself a pat on the back. Each team has only 27 outs per game and once they are gone, the game is over. Therefore, the players who produce the most positive impact while limiting the outs they generate are obviously gifted offensive players you want on your team. This is where the idea of Base-Out Percentage comes in.

Base-Out Percentage (BOP), created by Barry Codell, is a way to record this situation. The simplicity of what Mr. Codell developed is eloquent; the numerator contains all the bases gained, while the denominator records all the events that resulted in outs. Or, to put it even more clearly, you divide a players bases by his outs. Here is the formula:

(TB+BB+HBP+SB+SAC+SF) / (AB-Hits+CS+GIDP+SAC+SF)

Last season's BOP leaders are to the right. These 10 hitters all recorded more bases in 2006 than the outs they produced, making them excellent offensive weapons (Nick Johnson and Jermaine Dye were the only other hitters with a mark over 1.000). Some other notes:

Jose Reyes, who hit .300 last year, finished with a BPO of .776, below such luminaries as Kevin Millar (.791) and Emil Brown (.780). Though Reyes had a wonderful offensive season, .300-19-81-122-64, he also had 478 outs because of his 647 ABs gained batting leadoff for the Mets. Juan Pierre, who led the majors with 532 outs in 2006, produced a terrible BPO of .605, ranking him as the 148th best player in this survey. The worst hitter according to BPO for batters who had 502 ABs and hit at least .250 was the Pirates' Jose Castillo, who registered a scary-low .576 BPO.

It might take a bit of time to figure out BPO, and while other metrics have been developed in the almost 30 years since it was developed, BPO still can be a useful tool to gauge a player's offensive production.

SHORT HOPS

Chase Utley led all second basemen in HRs (32), RBIs (102), runs (131), hits (203) and OPS (.906) and threw in 15 SBs for good measure in 2006. Obviously, Utley reached .300-30-100-100-15 in 2006 and in so doing produced just the fourth such season in baseball history by a second basemen, so don't worry too much about his relatively "slow" start (.298-4-16-17-1).

A-Rod has reached 35 HRs, 100 RBIs and 100 runs in nine straight seasons to tie Jimmie Foxx for the longest streak in baseball history. Over the last 10 years an average A-Rod season has produced a .303-42-120-120-22 line, and for those of you into these kind of things, he is on pace for a totally unrealistic .385-119-290-222-9 season. Has anyone seen my copy of RBI Baseball lately?

It's a shame that phenom Felix Hernandez was placed on the DL with a strained right elbow, considering how dominant he was over his first two starts. In 17 innings he had allowed just four hits (.075 batting average against) and he was just the second pitcher over the last 50 years to pitch his first two games of the season allowing zero runs, on three or fewer hits, while hurling eight or more innings in each outing (Dave McNally in 1973).

An eight-time All-Star, Mariano Rivera saved 34 or more games for the ninth time in 10 years. 2006 also was the fourth straight season in which Rivera has kept his ERA below 2.00 and the ninth straight season in which he had a WHIP of 1.10 or better. So relax if you currently own Rivera (1-2, 7.11 ERA, 1.42 WHIP in 6.1 IP); by the time the season is over he will have his 30 saves and solid ratios.

Ray Flowers, a member of the Fantasy Sports Writers Association (FSWA) and the Society for American Baseball Research (SABR), can be reached with comments and questions at: fantasyfandom@yahoo.com. Also, "Get Your Head in the Game!" and don't forge to visit www.Head2Head.com, for the #1 Salary Cap Fantasy game in the industry.