BOSTON – He’s temperamental. He keeps late hours. He has been known to sulk. He carries a hefty price tag.

All that notwithstanding, Raul Mondesi would instantly become the Mets’ best outfielder if they are able to complete a trade with the Blue Jays for him.

The Mets and Jays discussed a deal that would make right field at Shea Stadium home for Mondesi. Met outfielder Matt Lawton and left-hander Glendon Rusch, the same tandem the Brewers asked for in exchange for Jeromy Burnitz, would go to the Jays.

The rap on Mondesi: If he’s playing for a non-contending team, he loses interest quickly. For a contender, when stroked by his manager, he’s capable of big things both offensively and defensively.

In 149 games this past year, Mondesi hit .252 with 27 homers and 84 RBIs. He’s a career .282 hitter whose best home-run year was 1999 (33) and best batting average (.310) came in 1997 – all with L.A.

He has among the strongest arms in baseball, and owns prodigious power.

Saying yes to the deal would require the Mets to expand their payroll in a way they had hoped to avoid. Mondesi has two years remaining on a contract that pays him $11 million in 2002 and $14 million in 2003.

If the Jays would agree to take David Justice ($7 million) instead of Lawton, the deal would be easier for the Mets.

The back-loaded nature of the deal makes sense for the Mets, who will have more payroll flexibility after bidding farewell to several free agents after the 2002 season.