The 29-year-old made five appearances during his stay with Shrewsbury and scored one goal during his month-long stay, but is keen to win back his place in Blades manager Danny Wilson's side.
"I needed a spell away from the club to get some games and thankfully I did that at Shrewsbury," Porter told the club's official website.
"It was good to be involved and the lads there were very welcoming towards me, as was the manager (Graham Turner) and his staff.
"I really enjoyed my time there, but I'm delighted to be back, fit and raring to go when selected."
Porter, an unused substitute in the Blades' 4-0 defeat at Stevenage on Saturday which saw them slip to fourth in the table, added: "The aim is still promotion and hopefully I can play my part in the weeks ahead."