The Bears, who will play the Lions on Nov. 13, cut Harris just over a week after he requested a trade before the Oct. 18 deadline.
The 29-year-old Harris was a second-team All-Pro last season and started the Bears' season-opening victory over the Atlanta Falcons before pulling a hamstring toward the end of the game.
Harris sat out the next three weeks to recover, and he returned to the lineup in an Oct. 10 loss to the Lions. In that game, Calvin Johnson beat Harris deep on a 73-yard touchdown pass from Matthew Stafford.
"I felt good enough to play. I'm not going to say I was 100 percent healthy when we played Detroit, but I felt good enough to play," Harris said Thursday on "The Waddle & Silvy Show" on ESPN 1000. "I'm 100 percent healthy now. I played last week. I thought I played OK last week, and I feel 100 percent healthy. I feel good."
Three days after the Lions game, the Bears decided to bench Harris. He was available to play as a potential backup in the Oct. 16 win over the Minnesota Vikings, but the team made the decision hours before kickoff to deactivate him.
The next day, Harris requested permission to seek a trade. Last Tuesday's trade deadline passed without a move, and Harris actually started against Tampa Bay on Sunday in London.
A sixth-round draft pick by the Bears in 2005, Harris has played in 88 career games with 82 starts over seven seasons, and has posted 416 tackles and 15 interceptions, in addition to forcing 12 fumbles.
ESPNChicago.com's Michael C. Wright contributed to this report.