Houston Texans receiver Andre Johnson left Sunday morning's practice with a pulled groin muscle, but coach Gary Kubiak says the injury doesn't appear significant.

Johnson missed nine games last season with hamstring injuries and was sidelined from the first organized team activities in the spring after arthroscopic surgery on his left knee. The five-time Pro Bowl selection started Sunday morning's practice and pulled up during a one-on-one drill.

"We don't think it's anything significant," Kubiak said. "Obviously, Andre's worked so dang hard to get back and get back on the field full speed, so it's disappointing."

Kubiak expects Johnson to miss "a few" practices, though he couldn't set a timeline. "We'll be smart with him," Kubiak said.

Johnson sat out 3-4 weeks after his knee surgery in May, and he turned 31 in July. After playing in all 16 games in 2008 and '09, Johnson sat out three games late in 2010 with a sprained right ankle. Last year, he hurt his right hamstring against Pittsburgh in October, then hurt his left hamstring against Atlanta in December.

Luck takes it slow

Andrew Luck didn't get much of a chance to show his strong right arm at Sunday morning's first training camp workout. Instead, the No. 1 draft pick is impressing new teammates with his command.

Receiver Austin Collie says Luck knows the Colts' new offense better than the veterans, and another receiver, Donnie Avery, likes Luck's take-charge approach in the huddle during the morning walk-through.

Luck is expected to do more throwing in a full-speed afternoon practice Monday.

Rams, Long agree

The St. Louis Rams and defensive end Chris Long agreed on a four-year contract extension through the 2016 season before the first practice of training camp. Long was seventh in the NFL with 13 sacks last year.

-- AP

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