TEMPE, Ariz. (AP) -- The Arizona Cardinals opened their three-day minicamp with intense competition for three spots on the offensive line.
Tight end, right tackle and right guard are up for grabs, with no clear front-runner.
Coach Bruce Arians says any decision won't be made until the players don pads and practice in training camp, which starts in late July.
One of the tight end candidates, second-round draft pick Troy Niklas, broke his right hand last week and Arians says he's out until training camp.
Other candidates at tight end are free agent signee John Carlson and returnees Rob Housler and Jake Ballard.
At right guard, the competition is between Earl Watford and Paul Fanaika. The tackle candidates are Bobby Massie, Bradley Sowell and Jake Potter.
"We'll just see when we put pads on and some of the pass rush slows down. With their shoulder pads on they can hit each other a little bit," Arians said. "The running game will be a big part of it. So is pass protection. But it all comes down to consistency mentally, or Cardinals can't be Cardinals."
Carlson, who has had concussion problems, signed a two-year contract with Arizona. Last season, he caught 32 passes for 344 yards and one touchdown for Minnesota. A second-round draft pick of Seattle in 2008, he has 177 career receptions for 1,096 yards and 14 touchdowns.
Arians said Carlson is bright and has picked up the system quickly, but the tight end said it hasn't been that easy.
"I'm excited. We're asked to do a lot of different things," Carlson said after Tuesday's workout. "It's difficult. It's challenging. It's not easy, but it's fun. We've got a group of tight ends I think can do a lot of different things on the field."
The players are helping each other even as they compete for a job, Carlson said.
"Every team I've been on, it's always competitive. We all want a job. Who doesn't?" Carlson said. "At the same time we're supporting each other and doing everything we can to be as good as we can be."
Arians said Carlson is a terrific receiver and "adequate" blocker.
Housler is a talented receiver still prone to dropping passes. He had 39 catches for 454 yards and one TDs last year. Ballard, formerly of the New York Giants, is a good blocker who caught seven passes for 75 yards and two scores a year ago.
The left side of the Arizona line seems set. Jonathan Cooper, the team's top draft pick in 2013, is back after missing all of last season with a leg injury. The team signed free agent Jared Veldheer as its much-needed left tackle. Center Lyle Sendlein is back to anchor the line.
The right side, though, is a work in progress.
Watford was a fourth-round draft pick out of James Madison a year ago. Fanaika started all 16 games at guard last year.
At right tackle, the Cardinals would love for Massie, a fourth-round pick out of Mississippi in 2012, to step into the role, but he has been prone to mistakes. Arians, though, said Massie has been "much better" this offseason. Sowell, also out of Mississippi, started 12 games at left tackle last year. Potter has filled in as a backup in recent years.
The mandatory minicamp follows 10 voluntary organized team activities (OTAs).
Temperatures were skirting triple digits when the Cardinals wrapped up their practice late Tuesday morning.
"That was our best practice so far," Arians said, "very spirited, very competitive on both sides. Offense won some, defense won some. It was a very good competitive practice. It went a little bit longer and was the type I was hoping for. There are still some young guys making mistakes that shouldn't be made, but the veteran group were practicing at a very high level today."
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