TAMPA — Never fall in love with a player in September or March. That’s wise advice when evaluating talent.

Expanded rosters in the final month of the season provide a watered-down product. Spring training offers an ocean of situations where too much stock can be placed in success and failure.

Still, only an idiot would ignore what is seen. After all, if organizations can bestow millions of dollars after watching a workout by a guy in shorts taking batting practice, why would you simply look past what is happening on the field under the palm trees?

What the Yankees have seen from Starlin Castro at second base this spring shouldn’t be ignored. After playing 38 games (29 starts) at second for the Cubs last season when he went from the starting shortstop to the bench to second base, the soon-to-be 26-year-old is still learning the nuances of playing on the other side of the bag.

However, in 10 exhibition games, he has made a play up the middle that reminded folks of Robinson Cano and chased down a short pop in the outfield. He isn’t a Gold Glover, but certainly isn’t lost while continuing to learn a new position.

A three-time All-Star in six major league seasons who has 991 hits before his 26th birthday on Thursday, Castro has danced under the radar while the focus of the Yankees’ camp has been on the health of the starting rotation.

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“I didn’t know what to expect and I am excited to be here. It’s been a good surprise and a great opportunity for me,’’ Castro said in a phone conversation Monday, a day off for the Yankees.

The new slide rule at second base will likely help Castro’s learning curve because it is designed to lessen contact with the middle infielder on double plays. Castro is athletic enough to make plays up the middle and toward first base. And his throwing arm is strong enough to overcome any problems with his feet turning two.

“I am learning every day, trying to feel comfortable,’’ Castro said about working with shortstop Didi Gregorius on the double play. “We have a good relationship and we communicate a lot. I think we have a good middle of the infield.’’

Since Cano left for Seattle following the 2013 season, the Yankees have used Brian Roberts and Stephen Drew at second with disastrous results. Roberts was done and released in 2014 when Drew was acquired from the Red Sox at the trade deadline. Drew was inked to a one-year, $5 million deal before 2015 and batted .201. Castro is a career .285 hitter whose subpar 2015, when he batted .265, dwarfs Drew even after Drew’s 17 homers are factored in.

So Castro, who has four years and $41.4 million left on his contract, isn’t Gregorius following Derek Jeter.

“He has been good and has fit into the club really well,’’ general manager Brian Cashman said of Castro, who cost the Yankees valuable right-hander Adam Warren in what is looking like a perfect example of having to give to get. “His performance has been good. It feels like he has been here.’’

According to a scout who has watched Castro, the Yankees are in for a treat.

“I think he is in for a big year. He is much better at second base than he was at short,’’ the scout said. “He has to keep focused. When [the Cubs] moved him to second, it seemed like he had a sense of freedom and that helped his offense. The Yankees did very well getting him.’’