Challinor joins Rovers
The 28-year-old will initially act as cover for Mike Fowler, who suffered a career-threatening triple ankle fracture during last weekend's pre-season friendly against Exeter City.
But caretaker New Lawn boss David Brown has not ruled out extending the deal, while the irony of Challinor's move from the Abbey Stadium will not be lost on Rovers supporters.
Jim Harvey's dismissal last week was believed to have stemmed from his application for the vacant manager's job at Cambridge.
This latest deal proves relations between the two clubs are amicable, although Blue Square Premier rules mean Challinor will be ineligible to play against his employers in the Blue Square Premier on September 5.
A central midfielder by preference, Challinor made his name as a Conference player at Aldershot Town, Exeter City and Rushden and Diamonds.
Cambridge paid £15,000 for his services last summer, only to put him on the transfer list after defeat in the play-off final against Torquay United.
He has been allocated number 24 at Forest Green and goes straight into the squad for this afternoon BSP opener against Kettering Town at the New Lawn.



Comment on this story