"This caught me as a surprise and it didn't catch me as a surprise," Harris said Thursday on "The Waddle & Silvy Show" on ESPN 1000. "It caught me as a surprise coming off a start and then going into the office on Thursday and being told I'm being released.
"But then again it doesn't catch me as a surprise because in the seven years I've been in the league I've experienced the highs and lows. I've been traded and things of that nature. I've been benched. I've come to realize that in this business nothing is for certain."
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 Detroit 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. "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 made the decision 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.
"They chose to go with the future and Chris Conte and Major Wright are the future," Harris said. "You don't spend third-round draft picks on guys to sit (them)."
The Bears drafted Conte in the third round (93rd overall) of this year's draft, and selected Wright in the third round (75th) in 2010.
"We're trying to win a championship, Bears coach Lovie Smith said after practice on Thursday. "The guys we're keeping here I feel like give us our best chance to do it."
In his second stint with the Bears after the club traded last year with Carolina to bring him back, Harris was in the final year of the contract he signed upon returning.
"They made changes at the positions they felt they could make changes at," Harris said. "You can't make changes at every single position on the team. It's just not possible due to depth and things of that nature. I'll kind of leave that one at that. Safety was one of the positions we had depth at and that was a position they felt they wanted to change."
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.
"It's football. It's the NFL," Bears defensive coordinator Rod Marinelli said. "This is what this league's about. We've just got the utmost respect for him. He is a tough, great competitor, great veteran. He brought a lot to us too. Obviously, those moves are always tough, because he's such a special person. We made a decision and now we move forward."
ESPNChicago.com's Michael C. Wright and Nick Friedell contributed to this report.