By Joseph Santoliquito

PHILADELPHIA, PA (CBS) — There is a little upheaval going on here and it’s only June. The Eagles have some holes that need to be solidified before the season and a glaring issue is up front on the offensive line, where Matt Tobin appears to be Todd Herremans’ replacement at right guard and Allen Barbre has been penciled in to replace the disgruntled Evan Mathis, the Eagles’ Pro Bowler who is holding out of OTAs, at left guard.

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“I think how things have played out, that’s where they like me, and sometimes it’s a guessing game for us too where (we’re aligned),” said Barbre, who was lost for 2014 with a high right ankle sprain in last season’s opener against Jacksonville. “I think it’s getting guys comfortable and playing well together. I feel comfortable just about anywhere anymore. I’ve played both sides of the line quite a bit. It comes down to where you feel comfortable the most. I cut my teeth on the left side, so it’s been natural for me to adjust.”

The Eagles will be a run-oriented team with DeMarco Murray, a one-cut power back, replacing the darting LeSean McCoy. Offensive linemen salivate over the fact that they get to bring the heat and engage defensive lineman, instead of peeling back and letting d-linemen attack them in pass protection. That’s what Chip Kelly is looking for most from his front—quick-footed, large guys that can reach the second level.

“It’s great to have running backs like we have, because a defense can’t really t-off on you,” Barbre said. “It makes it tougher to play the run, and I think makes things easier for an offensive lineman. I concern myself with what I have to do and make the block. I approach it like I’m going to block my butt off and open some holes.”

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Tobin, a 6-6, 290-pound three-year, undrafted veteran out of Iowa, is finally getting his chance. Where Barbre is forced to wait and see how the Mathis contract situation plays out, Tobin’s position as the starting right guard seems like it’s his to lose. He’s getting more reps at right guard. Tobin was hampered in 2014 by a left ankle injury, suffered in the Eagles last preseason game against the Jets.

“Once I came back last year, I was fine,” Tobin said. “I have to get better at pass protection and my balance on the run after my initial block. I have to maintain my balance after those first few steps. I’m getting a lot of reps out here and I think we have good coaching here and everyone sees how it works. I’m more comfortable. Last year, at this point, it was all left side, mostly at left tackle. This year, I’m getting both sides and my brain has kind of settled in on the left side now. I think my best position is wherever I’m playing. We have a lot of guys that can play multiple positions. We have a bunch of good guys, and guys who want to play with each other. If I’m playing left guard for two weeks, I’m comfortable at left guard. Now I feel more comfortable playing right guard.”

Now, moving from left to right, it looks like Jason Peters at left tackle, Barbre at left guard, Jason Kelce at center, next to Tobin at right guard and Lane Johnson at right tackle. It’s a group that hasn’t played a live down together.

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It’s a unit that will need to become cohesive—and fast.