He was offered a place at big spending Scottish Third Division club Gretna, and signed immediately. In his first season he led Gretna to the Second Division smashing records along the way. He shattered the record for most league goals in a season of 24 with 38 goals in only 30 games. During a friendly against Threave Rovers in 2006 he managed to score eleven goals in an 18–0 thrashing. He has not completely left medicine behind, as he continued to work one day a week at a Scottish hospital while at Gretna and worked one day a week at Wishaw General Infirmary before his move to the U.S.
Jeff Stelling, host of Sky Sports' Soccer Saturday programme, always makes reference to "The Good Doctor" having scored a goal whenever Deuchar's name appears on the vidiprinter.
During the 2006-07 season, he fell out of favour, but still managed to score 4 goals in 9 matches. On 1 December 2006, Gretna officially announced that Deuchar had requested a transfer.
On January 31 2007, he joined Northampton Town on loan until the end of the season and on 24 February 2007, Deuchar scored his first goal for Northampton in their 3–0 victory over Rotherham, which was his first goal in English football.
On 30 August 2007, Deuchar joined St. Johnstone on emergency loan until December 3 2007. During this three-month period he scored ten goals in fourteen games and helped the Saints to a Challenge Cup win, their first cup success in their history. On 3 December, he returned to Gretna and scored six goals in his eleven SPL games for the bottom club.
On February 26, 2008, Deuchar signed with Major League Soccer side Real Salt Lake. His final game with Gretna saw him score 2 goals against Rangers, but Gretna lost 4 - 2. He made his debut for his new club as a 70th-minute substitute for Real Salt Lake in their 1-1 draw with Chicago Fire on 29 March, 2008. He went on to score his first goal in a 3-1 defeat away at the hands of CD Chivas USA on the 05 April, 2008. Deuchar's flick-on headers have also been essential to the team as they have created many chances and goals for Salt Lake's speedier forwards, most notably Robbie Findley.
Deuchar is a company director in Town House Restaurants Ltd which owns the Wheelhouse restaurant, located close to the Falkirk Wheel in Falkirk and the new Boathouse restaurant at Auchinstary basin, in Kilsyth.