The signing is an indication that regular punter Brad Maynard either re-aggravated the groin injury that sidelined him last Sunday, or simply isn't ready yet to return.
Johnson, 32, punted for the Bears in last week's victory over Kansas City, averaging 49.8 yards gross and 39.3 net yards on four kicks. He had a long punt of 60 yards and one punt inside the 20-yard line before he strained a quadriceps while making a tackle. Placement specialist Robbie Gould then had to punt twice.
Thinking Maynard was ready to return, Chicago cut Johnson loose on Wednesday. Maynard was somewhat limited in practice during the week, however, and the Bears' may have decided that he needs more time to recover from the groin injury sustained in practice last week. So it appears that Johnson will punt in Sunday night's game against the Dallas Cowboys.
Johnson appears healthy, despite the quad strain.
For the second week in a row, the Bears released cornerback Ade Jimoh to clear a spot for Johnson.
Chicago special teams coach Dave Taub was an assistant on the Philadelphia staff in 2003, which was Johnson's first season with the Eagles, and so he is familiar with the five-year veteran.
Johnson was released by the Eagles on Sept. 1 after a training camp and preseason competition with free agent Sav Rocca, a former Australian Rules Football star. Although their statistics were fairly similar, the Eagles' coaches opted to go with the 32-year-old Rocca.
In 57 games, Johnson has a 41.6-yard gross average and a net average of 37.8 yards on 276 punts. The former Northern Colorado standout is regarded as a very good directional and hang-time punter.
Last Sunday's game marked the first contest that Maynard had ever missed in his 11-year NFL career.
The former Ball State star, a third-round pick by the New York Giants in the 1997 draft, has appeared in 161 games. He has a gross average of 42.2 yards and a net average of 38.1 yards on 920 punts. Maynard, who signed with Chicago as a free agent in the spring of 2001, has 291 kicks inside the opponent's 20-yard line and only 79 touchbacks.
Senior writer Len Pasquarelli covers the NFL for ESPN.com