The 19-year-old from London is trailing 15 places behind losing finalist Sally Barker with his single And I Am Telling You I'm Not Going and is currently sitting outside the top 40, according to mid-week sales figures from the Official Charts Company.
Sally, who lost out to Jermain in a public vote on Saturday, has stormed into the singles chart at number 35, with her cover version of Olly Murs' song, Dear Darlin.
Barker, who was mentored by Tom Jones, was bookmaker's favourite for the crown and a £100,000 recording contract. However, she is set to become the biggest-selling The Voice contestant this week when the final chart data is released on Sunday.
Fellow finalist Christina Marie's cover of The Power Of Love currently stands at 52.
However, talent show judge Ricky Wilson is set to beat all three contestants with his band the Kaiser Chiefs, whose new single Coming Home is currently at number 28.
The Leeds rockers' new album, Education, Education, Education And War, is also set to continue to occupy the top spot in the album charts for a second consecutive week.
Previous The Voice winners have also been notable chart flops. The show's first winner in 2012, Leanne Mitchell, failed to break the top 40 with her first single, Run To You.
Last year's winner Andrea Begley reached the highest chart position so far for a Voice contestant, when she came in at number 7 with her debut album, The Message.
British producers Sigma are on course to have their first number 1 single this weekend with Nobody To Love, knocking The Vamps into second place.