Brett Gardner is a free agent. So is Didi Gregorius, who did not get a qualifying offer from the Yankees. Aaron Hicks needed Tommy John surgery and will miss at least a few months next season.

That trio took 60 percent of the Yankees’ lefty plate appearances in 2019.

Now, Gardner is likely to stay a lifelong Yankee. Gregorius is more likely gone. And the benefactor of the switch-hitting Hicks missing time should be lefty Mike Tauchman. But as of this weekend, the only lefties or switch-hitters on the Yankees’ 40-man roster are Hicks, Jacoby Ellsbury — we will wait for you to stop laughing — Greg Bird (who could be non-tendered), Mike Ford and Tyler Wade.

Aside from the injured Hicks, there’s not a regular in that group. This continues a recent Yankees trend. They believed that pull-centric lefties such as Brian McCann and switch-hitter Mark Teixeira were being inordinately hurt by the shift, particularly at home where the short porch leaves even less fair territory to cover on the right side.

So the Yankees — the team of Ruth and Gehrig and Mantle and Maris and Reggie — gravitated to righties who tended to launch to the opposite field. As recently as 2015, the Yankees had a franchise record 3,443 lefty plate appearances. It was 1,775 last year — 27th in the majors.

The Yanks had the lefty batter-righty pitcher platoon edge in just 1,385 plate appearances last year, second fewest in the majors. It also was their second fewest ever, ahead of just the 1,377 from the 107-game, strike-shortened 1981 campaign.

The Yanks have remained an elite offense the past three years while leaning more right. Their .806 combined OPS from 2017-19 right vs. right is second best and their 387 homers the most. But I have grown suspicious that having so many similar righties in a lineup (Edwin Encarnacion, Aaron Judge, Gary Sanchez, Giancarlo Stanton, Luke Voit) provides an opposing manager with a strong bullpen a way to negate wide swaths of the lineup too easily with a righty specialist.

This feels like as area in which the six-month season and October differ. Over six months, against poor teams or against foes who can’t use the same top relievers over and over in a three-game series in June, the Yanks will feast. But in the playoffs, the bad teams are gone and the good clubs are using their best options each game.

GM Brian Cashman has said the Yankees will pick the best players regardless from which side they hit. I believe the Yanks have to find greater balance because they are playing for championships, not just the regular season. A few weeks back I made the case that if the Indians made Francisco Lindor available, the Yanks should essentially open their minor league system to get him because he fills so many needs — a switch-hitter with speed and power plus elite defense at short. If not Lindor, thoughts on greater balance:

Didi Gregorius: The Yankees’ evaluation was that 2019 Gregorius fell so far on both sides of the ball that they wouldn’t even risk the $17.8 million qualifying offer because he might take it. Will this version of Gregorius have a multi-year market? If he does and wants to go, the Yanks are out. Would he come back to a place he likes for, say, $10 million to re-establish his credentials another year removed from Tommy John surgery? If so, the Yanks could be in, especially because they like the person so much.

Jonathan Villar: Orioles GM Mike Elias has indicated finances will be a big deal when it comes to their arbitration eligibles, and Villar is looking at $10 million-ish for his 2020 walk year. Villar is versatile, including playing shortstop at about league average defense, so he could share that position with Gleyber Torres while both also move around elsewhere. Villar is durable (162 games last year). He is a switch-hitter who has added power (particularly from the left side). And he can run (31 steals).

One other item: The Yanks tried hard at the trade deadline on Toronto’s Ken Giles and Baltimore’s Mychal Givens to bolster their pen. Givens is two years from free agency. Perhaps the Yanks could unburden Baltimore of a lot of payroll by taking on Villar/Givens and filling the Orioles up with more low-cost prospects.

Freddy Galvis: Had the Yanks not added Troy Tulowitzki last year, Galvis was Option 2 to bridge until Gregorius was healthy. Another durable switch-hitter whose power has grown with time, especially from the left side. He is a far superior defender to Villar (or Gregorius). The Reds picked up his $5.5 million 2020 option. But the Reds could be a landing spot for Gregorius or see Galvis as a way to address other issues.

Jason Castro: The Yanks prioritize pitch framing with their catchers and like Kyle Higashioka’s skills plus potential power as a low-cost backup to Sanchez, which would mean letting free agent Austin Romine walk. But the Yanks should not guess on a backup to Sanchez, who has shown he is going to be on the injured list a few times a year. Plus, no Yankee has struggled more the past three postseasons, especially vs. righty pitching (.169 average in 89 at-bats). The game seems to speed up on Sanchez on both sides of the ball in October, and manager Aaron Boone might have to make some hard decisions about playing him.

The Yanks just hired Tanner Swanson away from the Twins to be their catching coordinator, and Castro is a free agent after three years with the Twins — so the Yanks will have lots of insights if they want his well-regarded framing and .851 OPS vs. righties last year.

Tucker Barnhart: Curt Casali took on a greater catching load for Cincinnati last year, and the Reds are a team connected with free agent Yasmani Grandal. So Barnhart could become extraneous. He has two years at $7.75 million left. He is a switch-hitter with a .760 OPS and all 11 of his homers from the left side last year. Plus, he is viewed as among the best pitch framers in the majors. Could the Yanks obtain Barnhart and Galvis in a single trade?