Shankland, a former apprentice at Stoke City, graduated through the Portuguese Vale youth team to make his debut in a 2–1 home defeat to Tranmere Rovers in a League Cup match on 28 October 1981. He finished 1981-1982 with thirteen appearances to his name.
During this time the club were twice promoted out of the Fourth Division. He was forced to retire due to an ankle injury, and became a window cleaner. He played seven Third Division and one League Cup game in 1983-1984, as McGrath was replaced by John Rudge.
Shankland suffered with ankle troubles throughout his career.
After two goals in a total of 29 appearances, he was given a free transfer in May 1986, but was forced to retire from football anyway due to an ankle injury sustained in a collision with an opposition goalkeeper. He was 22 years old.
He scored his first senior goal three days later, in a 2–1 win over Hull City at Vale Park. He signed as a professional in March 1982, and played three games in 1982-1983, as the "Valiants" won promotion out of the Fourth Division under John McGrath. He was restricted to just three appearances in the promotion-winning 1985-1986 campaign, though found the Netto in a 3–1 win over Wrexham at the Racecourse Ground on 8 March.
