In 2008 the Yankees were the second-worst defensive team in baseball based on Defensive Runs Saved. Their defense cost them 38 runs. Only the Royals were worse with 42 lost runs defensively.
In 2009 the Yankees improved dramatically defensively. By becoming an average defense overall (with 2 runs saved as a team overall), they improved by 40 runs. Using the rule of thumb that 10 runs represents one win, that's a four-win improvement due to their defense.
Where was the improvement? Most Yankee fans can pretty much guess: first base. Mark Teixeira stabilized the Yanks' infield defense. In 2008, Yankee first basemen cost the team 18 runs overall. This year, even in a down year for Teixeira, they improved by 19 runs to one run saved at first base.
One thing to caution you, however. Teixeira is only average when it comes to scoops (saving a bad throw from a fellow infielder). There has been a lot of speculation that Jeter's and Cano's improvement on defense this year is because of Teixeira's ability to handle bad throws. He can make that play, but that was something that Jason Giambi did well defensively for the Yankees last year too.
Overall, we have Teixeira as one of the best first basemen defensively in baseball. Here are the top five first basemen in baseball over the last three years based on Defensive Runs Saved:
Defensive Runs Saved
2007-2009 | | Albert Pujols, Cardinals | 56 |
| Casey Kotchman, Braves | 35 |
| Kevin Youkilis, Red Sox | 22 |
| Lyle Overbay, Blue Jays | 17 |
| Mark Teixeira, Yankees | 15 |
| Joey Votto, Reds | 15 |