The squad marks the return of Warriors' captain Jon Petrie, who missed the Bank of Scotland Corporate Autumn Tests through a shoulder injury.
Hadden is pleased to see a rejuvenated JP – his captain in his first two Tests as national coach against the Barbarians and Romania last season – back in the frame.
"It's great to have him back. I'm satisfied with his form and I know he can contribute in other areas too," he explained.
Graeme Morrison and Euan Murray are rewarded after some fine performances since returning from injury. They join Glasgow team-mates Dan Parks, Scott Lawson, Craig Hamilton, Rory Lamont and Andy Henderson, who all featured in Scotland's Autumn internationals.
Scotland squad for training at Murrayfield Monday 23 January – Thursday 26 January
Backs – Mike Blair (Edinburgh Gunners)*, Chris Cusiter (Border Reivers)*, Marcus Di Rollo (Edinburgh Gunners), Andrew Henderson (Glasgow Warriors), Sean Lamont (Northampton Saints), Rory Lamont (Glasgow Warriors), Ben MacDougall (Border Reivers), Graeme Morrison (Glasgow Warriors), Dan Parks (Glasgow Warriors), Chris Paterson (Edinburgh Gunners), Gordon Ross (Leeds Tykes), Hugo Southwell (Edinburgh Gunners), Nikki Walker (Border Reivers), Simon Webster (Edinburgh Gunners)
Forwards – Kelly Brown (Border Reivers)*, Bruce Douglas (Border Reivers), Ross Ford (Border Reivers)*, Dougie Hall (Edinburgh Gunners), Craig Hamilton (Glasgow Warriors), Allister Hogg (Edinburgh Gunners)*, Allan Jacobsen (Edinburgh Gunners), Alastair Kellock (Edinburgh Gunners)*, Gavin Kerr (Leeds Tykes), Scott Lawson (Glasgow Warriors)*, Scott MacLeod (Border Reivers), Andy Miller (Border Reivers), Scott Murray (Edinburgh Gunners), Euan Murray (Glasgow Warriors), Jon Petrie (Glasgow Warriors), Craig Smith (Edinburgh Gunners), Simon Taylor (Edinburgh Gunners), Jason White (Sale Sharks) captain
Not available for selection through injury: Simon Cross (Edinburgh Gunners), Rob Dewey (Edinburgh Gunners)*, Simon Danielli (Border Reivers), Iain Fullarton (Saracens), Scott Gray (Border Reivers), Donnie Macfadyen (Glasgow Warriors), Robbie Russell (London Irish), Gregor Townsend (Border Reivers), Andrew Wilson (Glasgow Warriors)*
*= Member of Scottish Institute of Sport