'American Idol' Castoff Scott Dangerfield -- I Got NO CLASS ... But That's About to Change

Former "American Idol" contestant and out-of-work substitute teacher Scott Dangerfield was booted from the show last week with ZERO job prospects -- but TMZ has learned, the school where he used to work wants him back!!!

Scott tells TMZ, he's been on the hunt for a new teaching gig ever since he got the chop ... but given the time of year, and the struggling job market, it's an uphill battle.

Scott's been getting several job applications together since leaving the show -- but HE CAN STOP NOW ... because the principal at Riverside University High School in Milwaukee (where Dangerfield worked before "Idol") wants to rehire him.

The principal tells TMZ, Riverside would welcome Dangerfield to substitute teach ANY TIME -- and if a permanent position opens up ... he definitely wants Scott to apply.

No surprise Riverside wants him back -- Scott was so dedicated to the school when he worked there last year, he turned down an invitation to Hollywood on "Idol" because he didn't want to desert his students.