After passing his medical today, and getting Football League approval Roberts will go into the squad to face Oldham at the County Ground on Saturday.
Andy King told Swindon's official website: "It certainly gives me another option and we now have real competition for places. He gives us power and pace that is something we haven't had for a while. What I mean by that is that he has the extra yard of pace
"The likes of Mooney and Parkin are 'link' players, but what we have with Christian is a player with the ability to take the ball over the top. The only other player we have like that is young Andy Caton."