With a dip in the free agency pool looming, Mark Teixeira may well find himself playing for a new club before season's end. AP

By John Rakowski, SportsGrumblings.com, Special to SI.com

Of all the major sports, baseball has changed the least over the decades. Baseball has more continuity, allowing for comparisons of players from different eras. You can't do this in football. For example, Johnny Unitas' statistics do not compare at all to Peyton Manning's. Heck, Unitas doesn't even compare to Jeff Garcia. Football has changed too much for the statistics to be meaningful between eras.

Baseball had a 70-year period in which player statistics were comparable, from the end of the dead-ball era in the 1920s to the early '90s. The early '90s saw some changes which led to an explosion of offense. More runs, more home runs and higher ERAs became the norm. Twenty-three hitters clubbed 50 or more home runs in seasons between '95 and '07. Before '95 it had been done only 18 times in all of baseball history. Regrettably, today's stats don't compare easily with those of even 20 years ago.

Three factors contributed to the offensive explosion of the modern era:

1. Performance-enhancing drugs -- Drug usage, especially amphetamines, had existed for a long time, but steroids and HGH became widespread in the '90s. Suddenly every power hitter looked like the Hulk.

2. Expansion -- Baseball expanded twice within a five-year span. In '93, franchises were added to Arizona and Colorado, and in '98 to Tampa and Arizona. Expansion added another 48 pitchers to major league rosters. Sluggers such as Ken Griffey Jr. feasted on these "Quadruple A" pitchers that should have been in the minors.

3. Ballparks -- Baseball began a massive stadium rebuilding effort in '92 when Oriole Park at Camden Yards opened. Seventeen ballparks have been built since then. Most replacements were more hitter-friendly than their predecessors. Outfield dimensions tended to be smaller in the new stadiums and foul territory was reduced.

Fortunately, there are no current plans to expand and the impact of drugs is lessening due to tougher testing practices. Ballpark rebuilding continues to be a factor, however.

The building frenzy brought us one new ballpark in '08, Nationals Park. Next season we will see two new stadiums in New York: Citi Field (Mets) and the new Yankee Stadium. The new Yankee Stadium will have the same dimensions, and the huge left-center gap. Citi Field's dimensions will be asymmetrical, unlike Shea Stadium. It will be deeper in right-center than in left-center. It's hard to tell how it will play, though in general it should be more hitter-friendly than Shea, a notorious pitcher's park.

Nationals Park plays fairer than RFK Stadium did. The power alleys in RFK were a pitcher's best friend. Nationals Park is more hitter friendly, though not exactly a hitter's park. It is in the middle (no. 15) in terms of runs scored, with slightly less than average in home runs hit (no. 20 out of 30).

The fantasy owner must take the stadium into account when setting lineups and when evaluating talent. For example, in head-to-head leagues, avoid pitchers starting in hitter-friendly stadiums such as Coors Field (Colorado), Cellular Field (Chicago) or Chase Field (Arizona). Double-down on pitchers starting in Petco Park (San Diego), PNC Park (Pittsburgh), Dodger Stadium and Shea Stadium.

You also need to factor in the home field when your fantasy players are traded. There are a number of well-known players on the trading block. The change of venue could give their stats a boost or drag them down. With that in mind, let's take a look at some players who are, or could be, on the move.

For Better

Xavier Nady, OF, Pirates

Nady is having a career year and is on his way to career highs in HR, RBIs and average. Nady (.327, 12 HR, 56 RBIs) is doing this despite playing in pitcher-friendly PNC Park. Nady is hitting .350 on the road versus .304 at home. So a trade to Arizona, for example, would enhance his fantasy value.

Mark Teixeira, 1B, Braves

Teixeira will be a free agent and Atlanta figures to trade him before the deadline. He hits well at Turner Field (.306), but he could end up in Arizona, Baltimore or Anaheim -- all hitter havens.