replace Chris Porter, who had signed for Derby County the previous day. He made his debut five days later, coming on as a second-half substitute in a 1–1 draw with St Mirren in the Scottish Cup. He made his first start and league debut a week later on Valentine's Day in Motherwell's 1–0 win over Hamilton, playing the entire 90 minutes as his strike partner David Clarkson scored the only goal of the game. Sheridan scored his first league goal for The Well a fortnight later, the winner in a 2–1 victory at Inverness. His only other goal for Motherwell came near the end of the season in a 3–0 win over Hamilton. On 13 August 2009, Sheridan joined Plymouth Argyle on a six-month loan deal. He made his debut in a 1–1 draw against Queens Park Rangers. He played 14 times for the Championship team but failed to find the net. Sheridan completed his loan spell at Plymouth and returned to Celtic on 14 January 2010. Later the same day he was again loaned out, this time to St Johnstone for the rest of the season. On his debut, on 17 February, he scored two goals in a 5–1 win against Hibernian. On 30 March he scored the opening goal for St Johnstone in a 4–1 win over Rangers. CSKA Sofia Sheridan signed a three-year contract with Bulgarian club CSKA Sofia on 13 August 2010. Sheridan made his debut in the 2–2 draw against League of Wales side The New Saints; CSKA won 5–2 on aggregate. He scored his first goal for the club in their 3–1 away win against Sliven. On 25 September, Sheridan scored twice in a 2–0 win against Montana. Changes of management, however, made it difficult for Sheridan to settle in Bulgaria. Trials in the United States and loan to St Johnstone On 7 June 2011, Sheridan appeared in a reserve match for American side Seattle Sounders FC. Sheridan started the game and scored in the 7th minute of a 2–0 victory over Vancouver Whitecaps FC. Following his spell with Seattle, Sheridan went on trial with their major rivals Portland Timbers, appearing for their reserve team. On 8 July, Sheridan joined SPL club Hibernian on trial, but instead decided to return to St Johnstone on a loan deal until January 2012. He made his second St Johnstone debut on 23 July against Aberdeen, and scored