At the moment, the Colts are hoping sufficient rest will be enough to overcome the injury which Bradshaw sustained during their 27-7 win over the San Francisco 49ers on Sept. 22.
However, a team source told Mike Chappell of the Indianapolis Star that surgery "might be needed."
Chappell also reports Bradshaw reportedly sought the advice of renowned orthopedic spine surgeon Dr. Robert Watkins regarding the issue in Los Angeles, citing an ESPN report dated Oct. 3.
Bradshaw also suffered a neck injury as a New York Giant in Week 2 of the 2012 NFL sesaon against the Tampa Bay Buccaneers, but shook off the effects to rush for 1,015 yards and six touchdowns for the year.
He hasn't practiced since the latest injury, according to Chappell, who spoke with Colts head coach Chuck Pagano on Wednesday.
"I'm planning on him being around. Certainly he won't be at practice. We've made some adjustments for that. Once we get some feedback, once we get some answers, then we'll know more."
The Colts head into Week 5 against a vaunted Seattle Seahawks team with a decimated running back rotation. Vick Ballard, who led the team in rushing last season, suffered a season-ending knee injury on Sept. 12.
Without both Bradshaw and Ballard, Trent Richardson and Donald Brown are expected to split carries for Indianapolis.
Indianapolis has been hampered with several injuries in 2013.
Tight end Dwayne Allen suffered a season ending hip injury against the Oakland Raiders in Week 1 while guard Donald Thomas tore his quadriceps the week after in a home loss to the Miami Dolphins.
In spite of these, the Colts are 3-1 and are in a first-place tie with the Tennessee Titans in the AFC Souththrough Week 5 of the regular season.