Two steps forward, one step back. Normally that’s a way of describing limited progress, but in this case it’s a description of the excellent outfield Bernie Williams has played of late.

Give credit to Lee Mazzilli. Mazzilli, who handles outfield instructional duties, approached Williams a few months ago about playing a more shallow center field. The four-time Gold Glover decided to give it a shot, and the results have been almost entirely positive.

While a few balls have occasionally landed over Williams’ head, plays like Friday night’s game-saving, diving grab wouldn’t have been possible in the past.

The Yankee center fielder made a sprinting, sprawling catch in shallow right-center with the bases loaded and two outs in the eighth. The Yankees had a 3-2 lead at the time and the play saved two runs.

“Mazzilli worked hard on this [with Williams],” Joe Torre said after the game. “Because first of all, you just can’t say, ‘Bernie, play more shallow.’

“[Mazzilli’s] got to make him understand he can do that. He worked hard on it, and it’s really been paying off.”