NEW YORK -- In their down hours, the Mets can feed Yoenis Céspedes as many fly balls as they like. Coaches can hit them over and over. Teammates can strike them during batting practice. Pitching machines can be reoriented to shoot balls skyward all morning, afternoon and night.

What the Mets cannot simulate are actual fly balls hit toward Céspedes in real games against other teams. So it was with some frustration that they watched Céspedes play three uneventful innings in left field during the Mets’ 6-0 loss to the Yankees on Sunday night, coming away from it with no better read on Cespedes’ defensive readiness than they had at the start of the day.

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That in itself will not upend the Mets’ plans for 2020. On most days, Céspedes figures to play either as a designated hitter or a powerful right-handed bat off the bench. His reps in left field should be limited, if they exist at all; the days of Céspedes providing Gold Glove-caliber defense on a regular basis disappeared -- probably forever -- when he underwent a trio of surgeries on his heels and right ankle in his mid-30s.

Still, the Mets would love to have the option, particularly because of what it would mean. A mobile Céspedes would mean a more athletic Céspedes, capable of running the bases with a little more verve than he showed in Saturday’s game at Citi Field. In that one, Céspedes sprinted halfway down the first-base line on a slow grounder to third base, only to reduce his speed to more of a jog by the time he reached first.

“That’s a good taste of something that he hasn’t done in a while,” manager Luis Rojas said of the baserunning test, adding that he hoped Céspedes would see some outfield action the following night.

Alas, it was not meant to be. The only ball hit even remotely in Céspedes’ direction was an Aaron Judge homer that sailed well over his head, over the wall and into the seats. Judge went deep a second time later in the game, leading a Yankees barrage that also included home runs by Gary Sánchez and Giancarlo Stanton. By the end of it, the Mets were glad these were only exhibitions. The Yankees outscored them, 15-3, in a pair of games in Queens and the Bronx.

Those results aside, the Mets have plenty of reason for optimism come Friday. One of the primary things in their favor is Céspedes, who might not have made the Opening Day roster had COVID-19 not pushed back the start of the season four months.

Now, Céspedes is not only a lock to make the team, but a possibility in left field.

“With coronavirus, it’s been a real tragedy what’s been going on,” Céspedes said this month. “But for me in the baseball sense, it’s helped me a lot having this break and being able to actually work out. I was working out seven days a week, waking up at 5 o’clock in the morning every day to get my body right.”

“Our hope is to play him both ends,” Rojas added, meaning on offense and defense. “We’re looking to see that progression keep going throughout this week.”

Two batters after Céspedes’ departure from Sunday’s game, Brett Gardner sent an opposite-field fly ball to the base of the wall that would have provided an excellent test. Instead, Dominic Smith chased after Gardner’s double as Céspedes watched from afar. How he might have handled it remained a mystery.

The Mets hope it won’t be that way much longer.

“We feel comfortable with him out there,” Rojas said. “We’re comfortable with him making plays there, getting his chances the next time he’s there in left. Unfortunately it didn’t happen tonight, but the way he’s running, the way he’s breaking off the bat on contact, he looked pretty natural.”