Emergency services were called out just after midnight to the scene, with four fire crews from Brant Broughton, Sleaford, Grantham and Nottinghamshire in attendance.
No other vehicle than the articulated truck was said to be involved, according to the fire service.
A Lincolnshire Police spokesman added that the incident happened close to the A607 junction: “The vehicle, a white HGV, left the road and came to rest in a field.”
The crews helped the driver from the cab, who was then treated by an awaiting ambulance crew.
The police spokesman said: “The driver, in his 40s, was taken to the Queen’s Medical Centre, Nottingham with injuries reported as serious.
“The road was closed and re-opened at 4.30am.”