The 20-year-old striker impressed at Spotland, scoring two goals in six appearances for Keith Hill's men, but he was brought back to his parent club due to Scunthorpe's injury problems.
Grant said: "I've been doing well for Rochdale but at the end of the day Scunthorpe is my club, I was just waiting for the gaffer to ring me to say come back.
"It's nice to be back, I'm prepared to fight for my place in the team and that's what I'm here for.
"I know I'm good enough to play in this team and it`s all about showing it. Being at Rochdale has been great, I've spent the last couple of months on loan there and the lads were brilliant."