Brandon Marshall made this catch Sunday vs. the Packers but was limited Thursday with a tight hamstring. (US Presswire)

Just when the Bears started regaining their health, another injury popped up in practice that threatened their most dependable weapon.

WR Brandon Marshall was limited in practice Thursday due to a hamstring that coach Lovie Smith said was "a little tight."

Marshall has accounted for almost one in every three net yards the Bears have gained this season (1,398) and has 107 of their 257 receptions.

LB Blake Constanzo, who replaced injured Geno Hayes (knee) at strong side last week, has a calf strain that also limited his availability in practice.

DE Shea McClellin (knee), WR Earl Bennett (concussion), CB Tim Jennings (shoulder), DT Henry Melton (collarbone) and Hayes all practiced Thursday on a limited basis.

Marshall hasn't missed playing time for more than two years, when a hamstring injury kept him sidelined for Weeks 12 and 13 of the 2010 season.

More fan fodder: LB Lance Briggs had initially backed up his sidekick, Brian Urlacher, in criticism of booing Bears fans and Chicago media who think Lovie Smith should be fired. However, he sang a different tune Thursday at Halas Hall.

"Fans are fans," Briggs said. "Fans pay for their ticket to go see a football game. It’s well within their right to boo, cheer, cry, laugh, do whatever. Whatever feelings come to them. As players, we go out, we play and we have a right to be happy, sad, upset, p’d off. And with the way that social media works now, everyone gets to find out how you feel more often than probably in years past. That’s just the way it works."

Turnover downturn: DE Corey Wootton has a good explanation for why the defense is averaging 1.3 turnovers forced the last six games after causing 3.5 per game in the first eight weeks.

"I think people are securing the ball a little more," Wootton said. "When they see guys like Charles (Tillman) coming after them, they’re putting two hands on the ball because they’re aware of that a little bit more.

"We’ve just got to do everything we can rallying to the ball and trying to get these turnovers.”

Stumbling, bumbling: DT Henry Melton was almost ashamed to talk about how he injured his collarbone against the Vikings, an injury that kept him out of a game and a half.

"It was kind of embarrassing, but it hurt," he said.

Melton basically just tripped over a player's foot and fell straight on his shoulder.

"I'm way more athletic than that play, so I call it being sloppy," he said. "I was running sideways and kind of stumbled over a bunch of guys' feet and just fell straight on my shoulder, and I was like, "Why did I even fall like that?"

Follow Bears reporter Gene Chamberlain on Twitter @CBSBears.