The 34-year-old's deal is the third short-term contract he has signed since joining the Championship club last summer after four injury-plagued years.
Barker only made five substitute appearances, but helped the Brewers avoid relegation and boss Nigel Clough sees him as a valuable squad member.
"I am not signing as a player expected to play 90 minutes or a couple of games a week," Barker told BBC Radio Derby.
"Six months is perfect. Physically I feel no different than I did in my mid-20s. I am fit enough and can still do sessions like everyone else. But I have a reaction with my knee so have to be careful."
The former Derby County centre-back said his aerial ability means both he and Clough are sure he can continue to contribute.
"There is definitely use for me in certain games," Barker added. "To play 90 minutes is a little bit too much, but you never know.
"If pre-season goes well and I am fit and able that would be lovely, but it is not something the gaffer and me are expecting."

Palm-sized fidget spinners have become the latest "must-have" for children.
But while some schools have banned the toys as a distraction, Castle Gardens Primary School in Newtownards, County Down, has taken a different approach.
The toys are being used as a teaching aid in some maths and English lessons.
Primary four teacher Heather Hutchinson is behind the idea.
"These crazes come into school and you either go with them or they're a complete annoyance," she said.
"The children wanted to know whose spinner was going to spin the longest, so I saw an opportunity for a maths investigation."
"They timed each other's spin, recorded it on a table and then put it on to a graph."
"It was an opportunity for something a bit different with their learning."
There are strict rules on when the spinners can be used in Ms Hutchinson's class, however.
She collects them at the start of the school day and only hands them out for certain lessons.
Her pupils have also honed their English skills by holding debates on whether they should be allowed in school and writing up their opinions.
Despite all of the children owning fidget spinners, they are divided on their role in school.
Eight-year-old Zach thinks they are a good idea.
"If you don't have neat writing you can spin them to help your finger muscles," he said.
But his classmate Anna disagrees.
"I don't think they should be allowed in class, as they distract the teacher and if you were asked a question you wouldn't know what to do as you'd be sitting fidgeting," she said.
Fidget spinners were originally developed as a way for children with Attention deficit hyperactivity disorder (ADHD) or autism to relieve stress.
When it is placed between the thumb and a finger, the child can give it a quick flick to trigger a spin.
There are many different types but the most popular is a small, three-pronged one with rounded ends.
There are many different types but the most popular is a small, three-pronged one with rounded ends.
There have been safety concerns, however, about ones with sharp edges or spikes.
Castle Gardens principal John Gray said his staff checked which fidget spinners children are bringing into school.
"It is using a degree of common sense," he said.
"Ones that are appropriate and safe will be used and if they're not, the children wouldn't be allowed to have them and they'll be returned to the parents at the end of the day."
But he does think the devices have their place in the classroom if used well.
"If the children are engaged and enthusiastic about something, the quality of learning will be higher," he said.
"We wouldn't use them for every lesson.
"It would be the occasional opportunity to use them in a numeracy or literacy lesson to engage the children in activities they would be doing anyway.
"For example, they would be doing graph work so we're using something to record real data they've taken themselves.
"They then plot the graphs, but because they're recording something that interests them we find the quality of what they produce is that much better.
"If you're interested in doing something, you're learning that much more."
Defender Shaun Barker has signed a new six-month contract with Burton Albion.
[NEXT_CONCEPT]
They are the new craze sweeping school playgrounds.