Parker will miss another five matches, having already served one, after the VFL Appeal Board dismissed his challenge on Monday night.
The Swans were hoping to downgrade the ban to four games, insisting the six match suspension was excessive.
Parker will not return to the AFL until well into July, at the earliest, after being unable to force his way back into the ladder-leading Swans when he recovered from a pre-season injury.
The appeal board rejected the submissions that the VFL tribunal made an error in originally handing down the six-game suspension for Parker's heavy bump on May 17 that resulted in Frankston opponent Josh Smith being taken to hospital.
Smith is expected to be sidelined for up to 10 weeks as he recovers from his injuries.
Parker has played 283 AFL games, winning three Swans best-and-fairests, and was a member of the club's 2012 premiership side.
With his glowing CV, the 31-year-old midfielder was expected to waltz back into Sydney's best 23 once he was fit again following a broken arm suffered in February.
But with the Swans dropping just one game this year and Isaac Heeney and Chad Warner dominating in the midfield, Parker was relegated to three appearances in the VFL.
He will now be restricted to merely training for five more weeks until he can play another competitive match.
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