Players have until midnight to report.
The team's first public practice at Olivet Nazarene University is scheduled for Thursday at 2:30 p.m.
ABC 7's Mark Giangreco and Rafer Weigel will both be in Bourbonnais. Rafer will be tweeting throughout camp. Follow him: @RaferWeigel
The Bears made big changes during the offseason. Now, it's time to deliver.
With Pro Bowl receiver Brandon Marshall in the fold and more depth on the roster, the Bears believe they are poised to make a big run after falling apart last season.
"Our expectations are always high," Pro Bowl linebacker Lance Briggs said.
At the moment, they're soaring.
The Bears believe they have narrowed the gap with Green Bay and Detroit in the NFC North. Even so, it would be premature to raise a banner or plan a parade.
A big boost came last week, though, when they locked in Pro Bowl running back Matt Forte, who signed a four-year, $32 million deal, with more than $18 million guaranteed.
Even so, the Bears are still staring at some big obstacles -- particularly in their division.
The Packers and Lions are loaded, but the Bears are coming armed after a disappointing 8-8 finish. Season-ending injuries to Jay Cutler and Forte exposed a lack of depth and buried a team poised to make a playoff run, ultimately costing general manager Jerry Angelo his job.
Briggs believes this could be the best team he's played on, and he's been on some good ones: the 2006 Super Bowl team and the NFC runner-up two years ago.
Other players have made similar statements in recent months. All they have to do is back them up. The Bears were looking good last year, but everything changed quickly.
They were finishing off San Diego on Nov. 20 to go to 7-3 when Cutler broke his right thumb trying to help make a tackle following an interception, sending Chicago into a tailspin.
Adding to the Bears' pain, Forte sprained a ligament in his right knee against Kansas City on Dec. 4 and missed the rest of the season. With the star quarterback and running back out, Chicago didn't have a chance.
The free-fall led to an overhaul.
Besides letting Angelo go, the Bears parted with Mike Martz after two seasons. He had an expiring contract, and Mike Tice got promoted from offensive line coach to coordinator.
Phil Emery wasted little time revamping the roster.
He gave Cutler a top-tier receiver -- something Angelo did not do -- when he acquired Marshall in a trade with Miami, and reunited the quarterback with one of his favorite targets. They put up big numbers together in Denver, and Cutler certainly is glad to have him.
He's also happy to be working again with quarterbacks coach Jeremy Bates, one of his mentors with the Broncos, and he certainly doesn't mind being in a system where he figures to take less of a pounding.
Instead of the deep drops, Cutler figures to move around the pocket and get the ball out of his hands quicker. The Bears believe that will take some pressure off a line that has struggled in recent years and remains one of the team's biggest question marks.
Cutler said the system is tailored more to his strengths and will resemble what he ran in Denver.
"It's kind of a mixture of some stuff Mike had done in his past, stuff Jeremy has, and he learned even more in Seattle, so it's a mixture of a lot of different things," he said.
If Cutler does get hurt, the Bears believe they are in a better position to absorb the blow. They signed Jason Campbell after Caleb Hanie failed as the fill-in starter late last season.
They also added depth at running back and gave themselves some insurance in case Forte holds out by bringing in Michael Bush. Chicago beefed up special teams, but questions remain about the effectiveness of both lines, not to mention the age on defense.
Even so, the Bears appear to be in a competitive spot.
"I think last year's team was pretty good when we were 7-3 before the injuries hit us," coach Lovie Smith said. "We have added some more good football players to that core. So we're feeling pretty good about our group."
The Associated Press contributed to this report.