"They're the two clubs that don't try to pick up the pace," said West, the chief of the umpiring crew working the three-game series, according to the report. "They're two of the best teams in baseball. Why are they playing the slowest?"West actually answers his own question - the reason that these two teams are the slowest is because they are the best.
"It's pathetic and embarrassing. They take too long to play." he said, according to the report.
Is it true that Posada and Martinez visit the mound too much? Yes. While the extra mound visits and batters stepping out of the box are annoying, they are not the reason why the games take so long. If the catcher never visited the mound and the batters never stepped out of the box, at best, 7-10 minutes (that's being generous) would be shaved off of the time of game. A look at some pretty basic stats reveal the real culprit.
In 2009, the two teams in all of Major League Baseball who's hitters saw the most total pitches were the Yankees (1st) and the Red Sox (2nd). Over 162 games, the Yankees saw 25, 049 pitches - the Red Sox saw 24,980. For comparison, the Major League average was 23,866 - the Giants, the 30th ranked team, only saw 21,091 pitches over the course of the season. So the Yankees and Red Sox saw over 1,100 more pitches over the course of the season - or about 7.3 pitches per game more than the average team.
In 2009, the Yankees and Red Sox were first and third, respectively, in runs scored per game. They were first and second in fewest strikes seen, 28th and 30th in the percentage of pitches they swung at (The 2009 Red Sox only swung at 26% of the pitches they saw while the Giants swung at 50% of the pitches they saw). The two teams at the top of MLB in OBP and SLG -Yankees (.362/.478) and Red Sox (.352/.454) the Major League average was .333/.418.
When these two teams are not batting, they take more time on defense than most teams. In 2009, the Yankees (6th) and Red Sox (1st) were among the teams who's pitchers threw the most pitches. Their pitchers strike out a lot of opposing batters - Yankees (4th), Red Sox (7th).
So to recap - At the plate, the Yankees and Red Sox see more pitches, swing at fewer of them, take more walks, make outs at a substantially lower rate than the rest of the league, when they hit the ball they get more extra base hits and score more runs. When those two teams play each other you get longer and more plate appearances, it takes longer and is more difficult to record three outs and both teams score a lot of runs. On the mound, the Yankees and Red Sox pitching staffs strike out a lot of opposing hitters and take more pitches to record outs. Put the two teams together and it takes a long time to record 54 (or 51) outs.
I didn't look up time of game data by opponent but I would be willing to bet that when two good teams play each other, the games are longer. When two lousy teams play each other, the games are shorter.