The Mets  made it official and announced the five-year, $25.5 extension for Jon Niese, who, if he lives up to expectations will make that a bargain.

Premium left-handers are in high demand and Niese has already shown a high upside. Throw in two team option years and the deal could rise to $45.5 million.

The Mets have been targets for bad contractual decisions, but this is a sound move because it will enable them to avoid the arbitration and free-agency issues for the next five years.

All contracts represent a gamble, and any thing long term with a pitcher is such, but because of Niese’s age and upside, they are locking him in to a reasonable deal. This is nothing like the Oliver Perez fiasco.

Niese called the deal a blessing and a relief.

“It means a lot,’’ Niese said. “It’s a relief. It’s just a burden off my shoulders. It’s something I don’t have to think about when I go out and pitch. I can just go out there and pitch, have fun and help the team win.’’

Niese will make his season debut tomorrow afternoon against the Braves.