[21] After undergoing knee surgery, his comeback was delayed until the end of February[22] and he returned to full training and reserve team action at the start of March.

In Derby's next game, against Coventry City a week later, Leacock was forced off at half time with knee ligament damage, and was ruled out for the rest of the season.

[25] Leacock returned to full training in time for Derby's pre-season campaign and started the 2010/11 season as Derby's first choice centre back (alongside Shaun Barker) and played the full 90 minutes of each of the opening eight league and cup games of the campaign, even notching the first goal of his 91⁄2 year senior career, on 18 September 2010, against Barnsley at Oakwell in a 1–1 draw.

[26] He made his 100th career league appearance in a 5–0 win over Crystal Palace on 25 September 2010 but sustained a hamstring injury which ruled him out for several weeks.

[27] He returned to the first team ahead of schedule on 16 October 2010, reuniting with Barker at the heart of the Derby defence as they ran out 3–0 winners over Preston North End.

Leacock held his place in the team over the next two months but came in for severe criticism from Derby manager Nigel Clough after his performance in a 5–2 defeat by local rivals Nottingham Forest.

[28] After this, Leacock made only three starts over the next 12 months before it was announced that had left the club by mutual consent and was set to sign for League One side Leyton Orient.

[33] Leacock joined Whitehawk on 2 October 2015, after Crawley failed to renew his initial one-year contract deal,[34] making his debut in a 6–0 home win against St. Albans City the following day.