With the Yankees reaching the one-quarter mark of the season two games below .500, in fourth place in the AL East, and having just watched the Tampa Bay Rays make a historic move to first place on their backs, there can be no doubt that if the George Steinbrenner of 20 years ago was still running the Yankees, heads would have rolled by now.

The Boss made 10 in-season managerial changes, and while there was no pattern to the timing — sometimes you had to wait for Billy Martin to do something offensive before you could fire him — he wasn’t above the precipitous change, removing Bob Lemon after 14 games in 1982 and Yogi Berra after 16 games in 1985. Coaches came and went as well, with it being par for the Yankees to run through eight or 10 of them in a season. The Boss was viewed as a destructively impetuous owner when he made those moves; for the Yankees of 2008, a change to the coaching staff might prove to be a measured response to the struggles of the team’s offense.

Hitting coach Kevin Long is highly regarded by the players, and has the additional credential of having presided over an offense that scored nearly a thousand runs last year. The 2007 Yankees led baseball in runs scored, in batting average, on-base average, and slugging percentage. They were first in their league in home runs, third in walks, and even ranked fourth in stolen bases. They did this despite having no regular first baseman, poor production at designated hitter, a slowdown from Derek Jeter in the second half, an inconsistent season from Johnny Damon, and deep season-opening and closing slumps by Melky Cabrera.

Two names are notable for their absence from the preceding list, and thus even more noticeable by their absence this season. Alex Rodriguez came out of the gate on fire last year, essentially winning the MVP award in April, while Jorge Posada hit a weird career peak at age 36, hitting an unaccustomed .338 and finishing fourth in the batting title race. Both were re-signed to large, and, relative to each of their ages, lengthy contracts after the season, because it was impossible to imagine the team without them — not in the emotional, this-just-wouldn’t-be-the-Yankees-without-you way, but in the more important sense of their being, at least for moment, irreplaceable. The falloff from these two players to any who would have been available to the Yankees seemed unimaginably large.

As it turns out, that estimation was wrong in one regard: The falloff turned out to be easily visualized; thanks to injuries, the Yankees are seeing it now. Rodriguez and Posada are absent, and their replacements have been killing the Yankees. Second-string catcher Jose Molina started off the season with one of the little hot streaks that, throughout his career, have contrasted so strongly with his general offensive ineptitude, going 12-for-33 (.364) with seven doubles in his first 10 games. Since then, he’s hit .073 AVG/.114 OBA/.098 SLG (3-for-41). Rodriguez’s main replacement, Morgan Ensberg, has hit .188, all singles.

The injuries to Rodriguez and Posada constitute the biggest exculpatory factor in the offensive decline which has seen the team fall from more than a run above the league average in runs scored per game in 2007 to just .15 runs per game above average this season, but do not excuse all. The Yankees have become a sorely impatient team this year, with a walk rate that ranks 23rd in the majors. Restoring Rodriguez and Posada to the mix would probably enhance the team’s selectivity in the long term, but as of the time each went out of the lineup, they, too, were uncharacteristically hacking instead of taking ball four and lagging behind the current team rate.

In all, the Yankees are seeing an average number of pitches per plate appearance, but these plate appearances are not resolving favorably. Given that the personnel on the Yankees includes a number of players who have traditionally shown better eyes, this would seem to be as much a matter of approach as actual skill, which is to say that Molina may not have the innate baseball ability, training, or mind-set to take pitches, so to expect him to do so, even at the behest of the team’s hitting coach, would be unrealistic — in baseball, 32-year-old players rarely learn new tricks. The same, however, cannot be said of other players.

Jeter is the canary in the coal mine here. This year, he has walked in about 4% of his plate appearances, less than half the major league rate. He has been more impatient than at any time in his career, seeing just 3.3 pitches per plate appearance. It’s hard to get to ball four when you’re making out on three pitches. Jeter’s career number is closer to 3.8, and that tiny, fractional difference is all that stands between a productive .300 batting average and a soft one. Jeter is, at press time, batting .305, but with just one home run and only six walks, the Yankees aren’t getting much more than league-average slugging and on-base percentages. It is surely better to get that from your shortstop than not, just as it would be better to have Posada’s impatient .300 in the lineup instead of Molina’s sucking void, or Rodriguez’s power instead of Ensberg’s strikeouts.

Still, when you put it all together, adding in Robinson Cano’s season-long status as one of the two or three worst hitters in all of baseball, as well as the fact that while some Yankees are hitting well, none have been especially consistent or hot, you have a team that is not hitting up to its capabilities. If a coach can’t get his players to do that, then what is he there for?

Mr. Goldman writes the Pinstriped Bible for yesnetwork.com and is the author of “Forging Genius,” a biography of Casey Stengel.