• Takes minor shots at Derek Jeter and compares him unfavorably to Alex Rodriguez.
• Believes trading Alex Rodriguez would be the wrong move.
• Mentions Jeter's past postseason failures, lack of clutchiness, and poor defense before Rodriguez's arrival.
• Mentions RFg and Win Shares to back up its opinions.

But what is lost in the argument about Rodriguez is his quite significant contribution to the Yankees. And no one benefits more from his presence than Derek Jeter. Jeter has never been considered a top defender, despite his sparkling reputation, and he was on a downward spiral in the years before the Yankees acquired Rodriguez.

From 1998 to 2003, Jeter performed below the league average for shortstops each season in a statistic called range factor per game, which shows how many plays (putouts plus assists) a fielder makes a game. He bottomed out in 2003, with a 3.65 RFg, a low figure in a season when the average major league shortstop recorded a 4.13. He also turned 29.

For comparison, Rodriguez never recorded a RFg below 4.3 as a starting shortstop, and the category has been led the last two seasons by Rafael Furcal of the Dodgers, who had a 4.99 in 2005 and a 4.88 in 2006.

The season he turned 30, which happened to coincide with the Rodriguez trade, Jeter suddenly turned a corner. His RFg improved to 4.32, and he was awarded a Gold Glove. The next year, 2005, was even better, with Jeter improving to 4.56 and winning another Gold Glove. With Rodriguez struggling through a difficult year in 2006 — and his fielding suffering — Jeter again regressed to below average, with a 3.97 RFg.

After Rodriguez’s arrival, Jeter’s fielding percentage remained fairly constant with his .975 career mark, meaning the only difference in his game was that he was getting to more balls put in play.

There are two possible explanations for Jeter’s transformation from a poor shortstop to a Gold Glove contender: either he developed more range at 30, an age when most players are beginning to decline, or he benefited greatly from having a Gold Glove-caliber defender at third base, which allowed him to cheat to his left, a weakness highlighted by many scouts.

Rodriguez certainly struggled this season in clutch situations, but his struggles were nothing that other Yankees, including Jeter, have not gone through.

While Jeter is often talked about as one of the great clutch performers, he has had his share of problems, including hitting .152 in close-and-late situations in 2003, far worse than Rodriguez’s .237 average in those situations this year.

Despite his reputation as Mr. November for a clutch hit in the 2001 World Series, Jeter went 6 for 44 for a .136 average that year in the American League Championship Series and World Series, which the Yankees lost to the Arizona Diamondbacks.

Using the statistic called win shares, which was developed by the baseball analyst Bill James to determine how many wins a player contributes to his team as a hitter and defender, Rodriguez has been more valuable to the Yankees over the last three seasons than Jeter. He has recorded 92 win shares as a Yankee, translating roughly to 30 wins for the team. In the same amount of time, Jeter has 85, translating to 28 wins. While a few wins may not seem significant, in two of the last three seasons, the Yankees have won the division by three or fewer games.

To replace Rodriguez’s average of 30.67 win shares a season since he joined the Yankees, Cashman would have to trade for two to three players who could combine to provide the same number. At that point the Yankees would already be at a net loss; those shares are accounted for by one player and not spread out over multiple positions where the Yankees have All Star-caliber players.

A player is often one good postseason from being considered a clutch hitter, and Rodriguez may look to Barry Bonds for inspiration. Going into the 2002 playoffs, Bonds was a .196 career postseason hitter. He then proceeded to hit eight postseason home runs and to compile a .471 batting average in the World Series, and that stigma has been shed.