McMahon recovered from a long-term Achilles problem that kept him sidelined for the final four games last season, but sustained an ankle injury in a summer friendly at York and missed the first three fixtures of the current campaign.
"It's been a long, hard summer for me personally and pre-season has been tough, but I got some reward for my hard work against Colchester," the former Middlesbrough right-back told the Blades' official website.
"I was delighted to be back in the thick of the action and it would have just been nice to complete my comeback with three points.
"The way the gaffer wants the team to play suits me and although I'm a defender first and foremost, there's nothing better than bombing on to support the attack.
"When you return to action it's easy to try and do too much too soon, but I'm experienced enough to settle back in quickly and take it all in my stride."
- Sports & Recreation