Minicozzi, 31, hit .298/.400/.470 with 12 home runs and 62 RBI in 315 at-bats with Triple-A San Jose in 2014. He has yet to appear in a regular-season game in the majors.
Hanigan, 34, is signed for two more seasons with a team option for 2017. He hit .218/.318/.324 with five home runs and 34 RBI in 225 at-bats in 2014.
Middlebrooks, 26, is eligible for arbitration for the first time after the 2015 season. He hit .191/.256/.265 with two home runs and 19 RBI in 215 at-bats in 2014.
Both pitched at a Class A level last season and averaged more than a strikeout per inning.
The pitching-rich Mets are dangling the 22-year-old Syndergaard, who struggled at the Triple-A level in 2014 with a 4.60 ERA and career-worst 1.48 WHIP. Syndergaard has fanned 474 in just 426 2/3 innings.
The very active Padres will have an entirely new outfield in 2015.
The 24-year-old Northcraft has yet to make his major league debut.
Prado is expected to assume the role of every-day third baseman for Miami. McGehee flashed virtually no power last season, but drove in 76 runs, batted .287 and committed just seven errors.
Peterson managed one hit in seven at-bats for the Athletics in 2013 and has not played since.
Lavarnway was hitless in 10 at-bats for the Red Sox in 2014 after missing extended time with a broken wrist.