Rigg, 28, links up with Workington following his release from National League outfit Dover Athletic.
He featured for the club on loan during 2017/18, scoring four goals in 12 appearances, and played in the club's recent 1-0 pre-season friendly win against Penrith.
Caretaker manager Steven Rudd said: "It's great to have Riggy back at the club.
"He's a local lad, a very good player and great character to have in the dressing room. We're delighted he's joining us."
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