Zach Thornton is back, and the Mets hope the prospect returns looking more like the pitcher they saw in his second outing than his first. 

Thornton will be used in Sunday’s series finale, either as a starter or a bulk reliever, though the exact way in which he will be used has yet to be determined, interim manager Andy Green said. 

“He will figure into our mix at some point tomorrow,” Green said before the Mets hosted the Red Sox on Saturday afternoon at Citi Field. 

The 24-year-old Thornton has made two appearances for the Mets this season.

In his debut, he lasted only 4 ¹/₃ innings against the Nationals, allowing four earned runs.

His second outing was much better, a six-inning, one-run showing against the Phillies. 

It is uncertain if Thornton will have an opportunity to remain with the team after the All-Star break, although the Mets are in need of a No. 5 starter after Nolan McLean, Freddy Peralta, Christian Scott and Sean Manaea. 

New York Mets pitcher Zach Thornton reacts after getting a double play ending the third inning. Charles Wenzelberg / New York Post

“The things that you love about the guys that have shown up here he has within him. He’s unafraid, he’s going to give you what he’s got,” Green said. “He’s going to step on the mound, he’s going to be aggressive. Most days, he’s going to fill up the strike zone, he’s going to attack. 

“He had a really good response against Philly. Gave up three really hard missiles to start that game, and then shut them down the remainder of the game. That’s who I believe him to be, that’s who he is. We have high hopes for what he can become and think he will ultimately be in the rotation. We think he’s the type of guy that will find a way to exceed every expectation of him.” 

The 6-foot-3 southpaw has had an uneven season at Triple-A Syracuse, pitching to a 4.02 ERA across 62 ²/₃ innings and 13 starts.

He has thrown the ball better of late, yielding three earned runs over his past 13 ²/₃ innings while striking out 16 batters.

Thornton is rated as the team’s No. 12 prospect by MLB.com.