2004. After the match, manager Martin O'Neill praised his performance, commentating that "he would never see the day that Wallace would score a hat–trick".Alan Thompson also said that Wallace was likely to succeed him in the future at left midfield positioned. However, he made little impact in either his league or European appearances, leading a loan enquiry from Inverness CT, whose bid was rejected. This led manager O’Neill respond to Wallace's bid rejection, saying the player remained part of his plan. After the transfer window closed, he continued to have his playing time, coming from the substitute bench for the rest of the 2004–05 season. With the club finished second place in the league and only won the Scottish Cup, Wallace went on to make twenty–one appearances and scoring three times in all competitions. With the arrival of new manager Gordon Strachan at the start of season 2005–06, Wallace made his first appearance of the season, starting a match against Artmedia Bratislava in the second leg of the UEFA Champions League second qualifying round and set up the second goal of the game for John Hartson before being substituted in the 54th minute, in a 4–0 win that was not enough for Celtic to overcome a 5–0 deficit from the away leg. However, despite announcing his intention to fight for his first team place, he found himself on the sidelines for the first few months and found his playing time, coming from the substitute bench. On 3 December 2005, Strachan began to play Wallace at left-back position in place of Mo Camara and he started his first match in the position, starting the whole game, in a 3–1 win against Aberdeen. However, this turned out to be a strange selection given Wallace's slight build and inexperience of playing in a defensive role. Strachan persisted with this team selection for several weeks to the bemusement of fans who could clearly see the player's lack of aptitude for playing in defence. This further highlighted his lack of positional awareness in playing in defence when he scored an own goal in the New Year game against Hearts at Tynecastle, although the club still won 3–2 on 1 January 2006. Towards the end of the season, new signing Mark Wilson replaced him at left back even though it was not his natural position (Wilson is a right back). But Wallace played in the Scottish