JACKSONVILLE – The circumstance is as difficult as can be imagined.

But Luke Butkus said while that's true, his focus now is to do the best job possible considering the circumstance and the task at hand.

Butkus, the Jaguars' assistant offensive line coach last season, was named interim offensive line coach on Thursday, a day before the team is scheduled to begin 2014 Training Camp practice. Offensive line coach George Yarno will be away from the team for "an extended period" to undergo cancer treatments, Head Coach Gus Bradley said Thursday.

Yarno will undergo the treatments in Spokane, Washington.

"You get into coaching, and you want this opportunity – no question," Butkus said Thursday, the day veterans reported for '14 Training Camp. "Unfortunately, this opportunity came with George Yarno being sick. He has a priority in Spokane right now that he has to take care of that's bigger than football, bigger than this.

"But he's very much a huge part of this room still. My role is to coach the offensive line this year, but no question this is George's room and I'm going to do whatever it takes to get this group, this team better."

Bradley said he has had multiple conversations with Yarno in recent weeks.

"He will not be with us for some time," Bradley said. "He's encouraged by the progress, and we're all rooting for him. We'll welcome him back with open arms when he comes back. He's such a big part of what we're all about."

Bradley said Butkus was among his first calls when assembling a staff in the 2013 offseason. Bradley worked with Butkus when the two were on the same staff in Seattle. Bradley served as the Seahawks' defensive coordinator from 2009-2012 and Butkus was there from 2010-2011 working with the offensive line.

"I felt like when we hired Luke we were very fortunate to get a guy of his capabilities," Bradley said. "It's always difficult when you lose a guy for some months like we will with George, but I think with Luke we're in a good spot. The transition should go pretty smooth."

Butkus said he has spoken to Yarno frequently in recent weeks.

"His spirits are great," He said, "he's doing great. He's battling and fighting this thing, just like we all are.  We're behind him 100 percent and he's doing well."

Butkus worked an increased role at times in the spring after Yarno's initial diagnosis, running meetings, doing installs and running individual drills. Plans to have Butkus assume the interim role were finalized a few days ago, Butkus said.

"We've been communicating all summer," Butkus said. "We weren't sure exactly what was going to happen. Gus all along has been kind of telling me we have to be ready to do this, so I had an idea in the back of my head."

Butkus said while he won't mimic Yarno's style exactly – "In order for me to coach it, I have to put my spin on it," he said – the approach to offensive line play will remain the same. Butkus will be assisted on the line by Matt Applebaum, the team announced Thursday.

Applebaum, who was named offensive line assistant Monday, will assist with game-planning and the line. He is entering his seventh year of coaching, having spent last season as the offensive line coach at Bucknell.

He was a graduate assistant and offensive quality control coach at the University of Miami from 2011-2012, when he worked under Jaguars offensive coordinator Jedd Fisch, who was then the coordinator at Miami. Applebaum worked as a pro personnel assistant, a college personnel assistant and an offensive coaching assistant with the Washington Redskins from 2008-2010.

"He's familiar with the offense," Butkus said of Applebaum. "He can come in and help any way possible."

Also around the Jaguars Thursday:

*Bradley addressed reports that wide receiver Justin Blackmon had been arrested Wednesday for marijuana possession. Blackmon, the No. 5 overall selection in the 2012 NFL Draft, has been suspended indefinitely by the NFL and Bradley and Caldwell had said throughout the offseason it was unlikely Blackmon would be in the team's plans this season. "It's unfortunate news," Bradley said. "Right now, all I can say is I just pray he gets the help that he needs."

*Bradley confirmed that four players – wide receiver Ace Sanders, cornerback Alan Ball, cornerback Aaron Colvin and linebacker Dekoda Watson – will not be available at the beginning of camp. Ball (ankle) and Watson (sports hernia) will begin camp on the Physically Unable to Perform list, with Sanders on the Active/Non-Football Illness list and Colvin (knee) on the Non-Football Injury/Illness list.

*The NFL announced Wednesday it has suspended Sanders for the first four games of the season under its substance-abuse policy. Sanders is allowed to participate in training camp and the preseason, although he said earlier this week he likely won't participate early in camp. …

*Bradley said he doesn't expect Ball's absence to be extended, and said the hope is to get Watson back sometime in camp and in time for the regular-season opener. ...

*Bradley also said second-year safety Josh Evans will be limited to start training camp. He underwent surgery to address bone spurs on May 20. …

*Linebacker John Lotulelei reported with a hamstring injury and Bradley said the second-year veteran could miss some time in camp. …

*Butkus said Bradley will discuss most personnel issues on the line, but said Thursday Austin Pasztor will be 100 percent to start training camp. He also added that he expects Pasztor, who started 12 games last season and who was limited in the offseason with a shoulder injury, to be the starting right tackle. "He's ready to go," Butkus said. "He's our right tackle."