The Yankees have had nutritional experts in the past, including one that the former owner George Steinbrenner borrowed from the United States Olympic Committee. But this time they seem to be making a more concerted push, and players who are more interested in prolonging their careers applaud the effort.

“Baseball in general is way behind the times when it comes to nutrition,” first baseman Mark Teixeira said. “But most teams over the last couple of years have put some effort into it, which is nice to see.”

Early in spring training, Sass spoke to the players and provided a video of best practices. They also heard an expert discuss the merits of sleep.

Sass got their attention by pointing out how certain foods could enhance their performance. For example, carrots really do improve night vision. And research from the University of Georgia shows that green vegetables can improve contrast vision, or the ability to see a white ball with red laces against a night sky. What hitter would not want that edge?

She also explained how sweet potatoes helped support the immune system, something vital for players facing extensive travel and a grueling schedule. Some players knew that, and most said the changes to the menu in Tampa this spring had been minimal.

“Grilled chicken breast and a sweet potato is fine for me,” said Teixeira, who came to spring training with a new gluten-free diet of his own and eats avocado almost every day.

Sass said she helped players find a personal chef, if they wanted one, or with anything else to do with food. For a typical game day, she recommends eggs (the so-called perfect protein) with lots of vegetables in them, oatmeal and fruit for breakfast. Lunch should include a lean meat protein, a quinoa grain bowl or a salad with olive oil vinaigrette and avocados. For dinner, grilled salmon, baked sweet potato, lots of grilled vegetables and fruit on the side.