The loss of Gray and Worrell are not necessarily going to have an impact on the secondary as much as it could on special teams. Last year, Gray and Worrell had 11 and nine special teams tackles respectively.
Johnson started 10 games last year and has the ability to be a physical safety, as did Gray, but with better hands.
"They know where he is, he's a big hitter and he really contributes a lot on the special teams," head coach Lovie Smith said of Johnson. "But we feel good about playing him as a safety."
The development of Harris softens the blow of the injuries.
"He knows the defense right now and he comes to work each day with his lunch pail so we like where he is right now as a rookie," Smith said of Harris.
The loss of Reese comes at a position the Bears do not enjoy the same luxury of depth.
Even though Joe Odom is the top reserve, he's missed time because of a concussion he suffered in the second preseason game. Rod Wilson injured his left leg against the Colts and it was heavily bandaged on Monday.
Reese started two games last season and could play either weak or strong side linebacker.
It's been nearly three weeks since Jerry Azumah had a scope on his hip. While the original diagnosis was that he would be sidelined three to four weeks, Smith said Azumah would not play in the preseason.
"He's doing more things right now," Smith said. "He's still on schedule. We're planning on him being in the lineup the first game, so that's where going on that one."
Fullback Jason McKie is recovering faster than expected from a torn pectoral muscle, but his status for the preseason remains uncertain according to Smith.
The offensive line was back at full strength on Monday. Center Olin Kreutz missed the game against the Colts because of illness, while guard Ruben Brown had to leave the contest because of an elbow injury. Both were back on the field and are expected to start against the Bills on Friday.