Team owner and general manager Jerry Jones met with some players on Tuesday morning and told them not to bother reporting to training camp in San Antonio on Wednesday because they will be cut.
Cutting Barber frees up $4.75 million in salary-cap space.
It is possible tackle Marc Colombo, who also met with Jones Tuesday morning, could be added to the list in the near future.
A fourth-round pick in 2005, Barber established himself as a tough runner with the ability to get in the end zone, but after signing a seven-year, $45 million deal in 2008 that included $16 million guaranteed, his production fell off.
He failed to run for 1,000 yards in any season and after scoring 33 touchdowns in his first three seasons he had just 18 in his final three seasons. He ran for a career-low 374 yards on 113 carries last season, missing three games with a calf injury.
Barber was scheduled to earn a $4.25 million base salary this season and a $500,000 roster bonus.
Colombo's agent, Jimmy Sexton, had told ESPNDallas.com on Tuesday morning that Colombo was being cut. A decision will have to be made quickly, however, with players reporting Wednesday.
Colombo is due a $2.6 million option bonus as well as a $1.9 million base salary and $500,000 roster bonus that would be paid out weekly during the season. By cutting Colombo, the Cowboys would save about $2.4 million in salary cap room.
If the Cowboys are to keep Colombo, he would have to take a reduced salary, according to multiple sources.
Colombo has expressed an interest in staying with the team and after a meeting with Jones it was revealed he could with a reworked contract.
Signed in 2005 after he was cut by Chicago, where he was a first-round pick, Colombo became one of the Cowboys' best finds in the Jones' era. He took over the starter's job in 2006 and held it through last season, battling through injuries.
He missed one game last year after having knee surgery in training camp and played through an elbow injury that limited his strength. In 2009 he missed the final seven regular-season games with a fractured fibula and high ankle sprain but made it back for the playoffs, although he struggled in the divisional round loss to Minnesota.
Brown, who was viewed as a competitor to David Buehler for the kicking job, was scheduled to earn $910,000 in 2011.
Davis, who signed a seven-year deal worth $49 million in 2007 as a free agent from Arizona, started every game he played for the Cowboys and was named to the Pro Bowl in each of his first three seasons.
The move saves the Cowboys $6 million against the salary cap this year. Davis was scheduled to earn $6 million in base salary and count $9.416 million against the cap in 2011.
When the Cowboys signed Davis, Jones hinted at the possibility of moving him to left tackle if needed, but Davis proved to be a dominant guard in his first few seasons. Davis, who turns 33 in September, struggled at times last year and was replaced by Holland against Tennessee but returned after Holland suffered an eye injury. Davis' play toward the end of the season was improved.
If the Cowboys end up releasing Colombo, then they will be breaking in a new right side of the line for Tony Romo. Rookie Tyron Smith is expected to start at right tackle and Holland has starter's experience but has only done so four times since coming to the Cowboys in 2008.
Calvin Watkins and Todd Archer cover the Cowboys for ESPNDallas.com. Information from The Associated Press was used in this report.