The 29-year-old has tweaked his hamstring and is currently receiving treatment but is anticipated to be fit for Castleford's Super League opener against Toronto Wolfpack on February 2.
The Tigers will face the Canadian club as part of double header at Emerald Headingley Stadium with Leeds Rhinos hosting Hull FC on the same afternoon.
Watts was one of Castleford's stand-out performers in 2019, earning himself a Steve Prescott Man of Steel nomination.
He played 30 times for the Tigers last season, but his preparations for next campaign have been disrupted.
He was called up to the England 9s squad for the Downer World Cup 9s in Sydney in October as England reached the semi-finals before losing 22-6 to New Zealand.
The former Hull FC player wasn't picked for Great Britain's tour of the southern hemisphere as they lost all four tests. Wayne Bennett's men were defeated twice by New Zealand and once by Tonga and Papa New Guinea.
Given the nature of his injury, Watts will miss some of Castleford's pre-season programme which starts with a clash against Bradford Bulls on Boxing Day.
The Tigers will then travel to the Halton Stadium on January 12 to face Betfred Championship side Widnes Vikings at 3pm.
A week later, Daryl Powell's side will face their opening day opponents, Toronto, in captain Michael Shenton's testimonial game at the Mend-A-Hose Jungle at 2pm.