Former Pilgrims boss Paul Hurst and ex-player Shaun Pearson will be in town for the contest, which kicks off at 3pm on Saturday, August 7 - one week before the start of the National League North season begins.
The contest also puts United assistant John McDermott against the club for whom he made 647 appearances.
“I think this one will be a really competitive game,” Elliott said.
“It’s just before our season starts so both teams will be where they need to be in terms of match fitness.
“There’s not a lot between us now in terms of league positions so I think it’ll be a really good game.”
The Mariners were relegated from League Two last season.
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