Hejda, 37, had one goal, 12 assists and averaged 20 minutes, 39 seconds of ice time in 81 games for the Colorado Avalanche last season. His four-year, $13 million contract with the Avalanche expired at the end of last season.
The native of the Czech Republic had a number of options ahead of training camp, deciding on the Blackhawks because of the potential fit, according to the source.
The Blackhawks are expected to add one more defenseman to their NHL roster. They have six in place with Duncan Keith, Niklas Hjalmarsson, Brent Seabrook, Trent Daley, Trevor van Riemsdyk and David Rundblad filling NHL spots.
Hejda could replace Michal Rozsival as a veteran who can rotate as the Blackhawks' sixth defenseman. Rozsival became a free agent after three seasons in Chicago.