Adam Ottavino is returning to the Mets’ stable. The right-handed reliever has agreed to a one-year, $4.5 million contract, according to multiple reports. Ottavino has spent the last two seasons in Flushing where he has pitched to a 2.62 ERA in 132 games. Ottavino had a $6.75 million player option that he declined at the beginning of this offseason, however, he now returns to the Mets for less money. The 38-year-old will likely return to his set-up man role with Edwin Diaz set to return as the closer after missing all of last season after tearing his patellar tendon in a World Baseball Classic …