| From | Team | Fee | Apps | Goals | To | |
|---|---|---|---|---|---|---|
| 2004 | Hibernian | - | 156 | 43 | 2009 | (Player) |
| 2009 | Burnley | £3,000,000 | 35 | 8 | 2010 | (Player) |
| 2010 | Wolverhampton Wanderers | £6,500,000 | 61 | 22 | 2012 | (Player) |
| 2012 | Sunderland | £12,000,000 | 94 | 23 | 2016 | (Player) |
| 2016 | Sheffield Wednesday | Free | 124 | 36 | 2020 | (Player) |
| 2016 | Olympique Marseille | Loan | 12 | 1 | 2016 | (On loan) |
| 2020 | Stoke City | Free | 72 | 12 | 2022 | (Player) |
| 2022 | Dundee United | Free | 33 | 9 | 2023 | (Player) |
| 2023 | Wrexham | - | 73 | 16 | 2025 | (Player) |