ST. PETERSBURG, Fla. — In many ways, it is obvious why the Yankees have been one of the best teams in baseball this year: They have one of the sport’s highest-scoring offense, one of its best bullpens and an average-but-improving starting rotation, all helping them to 103 wins (as of Friday’s 14-7 win over the Texas Rangers) and an American League East title.

But one aspect of the Yankees’ play this season has been trickier to evaluate: their defense. Depending on which metrics you choose out of the ever-expanding world of advanced analytics, Yankees fielders have been better than last year, or maybe worse, but probably close to average in the majors this year. One trend, though, seems clear: Their use of the shift — a popular tactic that atypically positions fielders to match a batter’s tendencies — has gotten worse.

Of course, it comes down largely to which tools are used for evaluation. If you look at outs above average, the 2019 Yankees have improved over last year’s squad. But other metrics, such as defensive runs saved (D.R.S.), show a downgrade for this season’s team — but only a bit below average.

And then there are the opinions from the players actually doing the defending.

“We’re above-average defensively,” said the Yankees’ D.J. LeMahieu, an All-Star multipurpose infielder. “I feel like we make all the plays we should make. And our outfield is really good.”