Mark Vientos has started just 15 games at third base this season, which makes any evaluation premature.

But the very early signs have been arguably more encouraging than the powerful bat he is wielding.

The new Mets third baseman — at least for the moment after Brett Baty was optioned to Triple-A Syracuse last week — has run with the opportunity on both sides of the ball.

His bat forced his way into the lineup, posting a 1.013 OPS with five home runs in his first 20 games of the season.

But there had been fewer questions about his bat after coming up through the system as a slugger without a true position.

Perhaps he is proving that he can make third base his home.

In the small sample size of 132 ¹/₃ innings at third this season, Vientos has yet to record an error, has registered plus-one Outs Above Average and has helped more than he has hurt.

He might not ever be an elite third baseman, but if can continue to play at least league-average defense, his bat could do the rest.

Of late, though, Vientos is not just playing average defense: The 24-year-old may have pulled off his best defensive play as a major leaguer in Washington on Tuesday when he dove down the third-base line, speared the ball and threw across the diamond from one knee to steal a hit from Nick Senzel.

His legs might not be the most mobile, but his arm has impressed.

A key, according to infield coach Mike Sarbaugh, has been Vientos’ trusting just his glove and not allowing his right arm to get in the way.

Little League coaches should continue to teach the use of the off arm as a backup, but major league third basemen have to trust one hand.

“Over on the corner, first or third, the balls get hit so hard to you,” Sarbaugh said recently. “It’s almost like you react better and your body’s a little more loose when you use one hand. So just getting [Vientos] to have the confidence to do that — I think that’s important for a corner position, and he’s been working on that.

“Think about a goalie in hockey. [Against] a slap shot, if they went with two, they probably wouldn’t move as quick.”

During his brief time in the majors the past two seasons, Vientos never looked as confident as he does right now.

Sarbaugh, who had been with Cleveland previously, had not seen that version of Vientos much up-close, but he has seen a difference in Vientos just over the past few months.

“He put a lot of hard work in this spring,” Sarbaugh said. “And I think a lot of the things that he was working on down when he was in [Triple-A] Syracuse, he’s improving. I can see the confidence coming.”