By JOEL SHERMAN

The Mets have thrown another player into the mix to be a potential backup or alternative to Luis Castillo by signing Jose Valentin to a minor league contract, the Post has learned.

Valentin would make $800,000 if he played in the majors.

Valentin was the Mets’ primary second baseman in 2006 when he hit .271 with 18 homers. He broke his tibia the following season and last year never played in the majors, leaving the Mets’ Triple-A team in June claiming mental and physical duress.