Swinton have signed young prospects Ben Warrilow and Liam Fishwick, but have allowed back-rower Dale Cunniffe to leave the club.
Warrilow, 21, began his career at Newsome Amateurs in Huddersfield and made headlines as a sprinter before joining Wakefield and then Warrington as a winger.
“He is sharp and very fast and is a good signing for us.
“(Ben) has looked really sharp in training. He is a really good signing and I am delighted to snap him up before anyone else did.
“We will drip feed him in over the next couple of weeks.
“Scrum-half is an important position and we want to make his transition into the side as easy as possible. We won’t rush him.”
Cunniffe has withdrawn from the squad due to work commitments, but Watson confirmed that prop Mark Thomas, who joined the Lions midway through last season from amateur club Eccles, is part of the squad for 2014.
Swinton start their Championship season with a trip to Halifax on Sunday February 16.