The experienced prop, 31, will be back in the line-up for Castleford’s must-win contest with Warrington Wolves at Wheldon Road having missed the last two games due to a ban for tripping.
Beaten Challenge Cup finalists Tigers must win their final regular round to qualify for the top six or their season is over.
Watts feels “freshened up” but admitted he has also been nursing an injury.
“I took a bit of a whack in the Hull game,” he recalled.
“I actually fractured my shin. I got through the following Wigan game as I was always going to be resting the week after that and it (ban) has been a silver lining just to get back fit.
“I’d got a stray boot. It’s caused my leg to bleed massively. Against Wigan, my full ankle had locked up with blood. Once you get a bang on the shin on the bone there’s no muscle for the blood to drain into.
“There were a few concerns about blood clotting. The main issue with that is there’s quite a lot of swelling within the calf and the ankle and obviously if that’s not managed correctly you are at risk of getting blood clots which can lead to quite severe endings.
“It’s taken me a few weeks to get that nursed up.
“But (physio) Matt (Crowther) has done a fantastic job of getting me fit and ready for this.”
Castleford know they will fail to make the play-offs if they do not win tonight but they have defeated third-placed Warrington twice in their three meetings so far this term.
Tigers coach Daryl Powell hopes to have Man of Steel Paul McShane and half-back Gareth O’Brien fit to line up, too, as they return from their own injuries.
It is potentially the final Castleford game for not only Powell, who joins Warrington in 2022 along with centre Pete Mata’utia, but retiring captain Michael Shenton and prop Grant Millington as well as departing players such as Jesse Sene-Lefao and Alex Foster.
Ex-Hull FC star Watts conceded: “It will be emotional but our season’s on the line.
“As far as all the efforts we’ve put in over the year, starting in pre-season right through now until last week’s game, it comes down to one game again and that’s the beauty of the sport.
“You can play all year long and pick up wins, pick them up here, there, but somehow every year it just comes down to three teams fighting it out for the play-offs.
“We were in there last year and we missed out so we know what that feels like.
“And there’s no way we want to be one of the teams on standby waiting for a call because of Covid.
“We’re wanting to put our feet firmly in the mix.”