Rivers spent a trial period at Portman Road earlier in the season, but Royle felt he was not good enough to be considered for a full move. However with Rivers at Crewe, the former Norwich man is likely to want to prove Royle wrong.
Speaking to the Ipswich Evening Star, Royle said: “When I invited Mark to come in for a trial I was looking for an extra midfielder. He did OK, but I just didn't feel at that stage that it would have been the right move for us.
“He's a nice lad and I did also have it in my mind that it might be difficult for him, being a former Norwich player.
“Although that wasn't my main consideration, I wondered if he might have to come in and be a storming success to be accepted. Sometimes it can be hard for players in those circumstances."