Source: Cardinals WR Floyd dislocates three fingers, out 6 weeks

Just as the Arizona Cardinals begin to prepare for a season with Carson Palmer back under center, the club on Wednesday lost one of his most important targets at practice, and could be without him when the regular season begins.

Starting wideout Michael Floyd left practice at Glendale, Ariz., with an injured left hand, walking off the field with a trainer after suffering the injury near the goal line on the field that hosted last season’s Super Bowl.

The club did not reveal the severity of the injury as of Wednesday night, but FOX Sports NFL Insider Mike Garafolo confirmed through a source earlier reports that the receiver dislocated three fingers and could miss six weeks.

Entering his fourth NFL season, the 6-foot-2, 220-pound Floyd has been the main downfield threat for a talented group of Arizona receivers that includes Larry Fitzgerald and John Brown.

Floyd, a 2012 first-round draft pick -- 13th overall -- out of Notre Dame, caught 47 passes for 841 yards and six touchdowns last season, down from his breakout 2013 year when he caught 65 passes for 1,041 yards and five scores.

Jaron Brown took Floyd's place with the first unit the rest of practice Wednesday.

Later in the practice, guard John Fullington was taken off the field in a cart with a left knee injury.

The Cardinals got some good news on the injury front, however, as head coach Bruce Arians announced Wednesday morning that the left knee injury suffered Tuesday by rookie first-round pick D.J. Humphries is only a hyperextension.

Humphries, trying to unseat Bobby Massie as starting right tackle, was one of 13 players sitting out Wednesday's practice with injuries.

On Tuesday, Palmer took a training camp day off when healthy for the first time in his NFL career, although he said he didn't like it.

"It was something that was set in stone months ago," the quarterback said Wednesday in his weekly meeting with reporters. "It was something I argued with for probably six weeks and then just gave up because I realized I was getting nowhere with it."

Palmer, 35, is coming off surgery to repair a torn ACL and he acknowledged the day off might have done him good.

"I think so," he said. "I won't admit that to them but I understand what they're thinking."

He said the plan is to have him take off every fourth or fifth day. On Wednesday, backup quarterback Drew Stanton had the day off. Stanton also is coming off a knee injury, although less severe than Palmer's.

Palmer took a tumble in Monday's practice, the first of the camp for the team in pads, but said it never fazed him.

"It looked a lot worse obviously than it was when I saw it on film," he said. "I didn't really realize what happened, especially because we were in a two-minute drill, and you're focused on what happened on that play, and then what you're going to do on the next play, and really didn't think twice about it."

Safety Tyrann Mathieu pushed running back Kerwynn Williams into Palmer's legs, knocking the quarterback over.

Palmer said Mathieu has checked on him a number of times since.

"He was more scared than I was," Palmer said, "a little more nervous than I was when it happened."

Mathieu said Tuesday that "my heart was in my behind" when Palmer went down.

New to the injured list, along with Humphries, were guard Earl Watford (knee), linebacker Darryl Sharpton (hip flexor), running back Marion Grice (hamstring) and tight end Ted Bolser (knee).

— The Associated Press contributed to this report.