PITTSFORD, N.Y. – For a football team that's going to pride itself on running the football, there are few greater tests in the NFL than the Buffalo Bills' defensive line.

Buffalo ranked fourth in the league last season in yards allowed and features two massive Williams' – Kyle and Mario – that need constant double-teams. Offensive coordinators do not enjoy preparing for the Bills.

"This is one of the best defensive fronts in the game," coach Mike Pettine said. "For our guys to go out and against them in live work – to me there is no way to have any substitute it for that."

After mustering 19 carries for just 45 yards (2.4 yards per carry) in the preseason opener against the Redskins, the Browns brought their running game to St. John Fisher College to try and get the wheels rolling.

Day 1 of joint practices with coach Rex Ryan and the Bills concluded Monday, and the Browns are still searching for momentum.

"The Bills defense, I thought, had the upper hand," Pettine said. "I think some of our guys had different tempos. They have to understand the guy across from them is going at game type speed, other than the live tackling part. We were inconsistent with our expectancy of what we were getting from the other side."

Despite the lack of tangible results, the mood remains sanguine within Cleveland's coaching offices and the locker room.

The Browns are still without speedy rookie Duke Johnson (hamstring) and veteran Shaun Draughn (thumb). Terrance West (calf) is still playing himself back into football shape after missing a vital week of practice when the pads went on.

Further, Browns offensive coordinator John DeFilippo kept many of the zone-blocking concepts installed a year ago. The language is similar. The five blockers up front are all the same. And because Cleveland has instituted a completely overhauled passing attack, much of the work in practice has been spent with quarterbacks Josh McCown and Johnny Manziel throwing all over the field.  

"We have three preseason games. We have a bunch of practices," left guard Joel Bitonio said Monday after practice.

But Pettine is saying his team, and specifically offensive line, has to want it more; has to be nastier. The intensity must be cranked up for Tuesday night's practice, which is closing in on being sold out in front of a raucous Bills crowd.

"Hopefully the offenses we'll rebound," Pettine said. "We will see."