One of the things waiting to be defined during the stretch drive of this Eagles season is what the running back roles are going to be, once Jay Ajayi is fully functional in the offense – something offensive coordinator Frank Reich indicated might be the case as soon as Sunday night at Dallas. It seems likely Ajayi will emerge as the dominant back, probably at the expense of Wendell Smallwood (a lot) and LeGarrette Blount (at least a little), but it would be a big surprise if Ajayi cut much into the snaps of undrafted rookie Corey Clement. Why? Because Clement is that guy that running backs coach Duce Staley said recently “battled, fought, scratched and clawed” his way into the discussion. Reich was asked this week about Clement’s five red-zone touchdowns this season, including that amazing Monday Night Football catch against the Redskins, when Carson Wentz somehow found Clement while being swarmed, then Clement soared at the sideline, plucked the ball, and came down with both feet inbounds. Reich referenced that catch, which he said was “just ability.” Then Reich said: “Some of it is just want-to. I think all of our players have a lot of want-to … Corey has that little bit of extra want-to. That’s always been something that stuck out about him, as far as I’m concerned, from Day 1.” Clement, 23, is coming off a three-touchdown afternoon against the Broncos. His two rushing touchdowns and one receiving TD in that 51-23 victory made him the first Eagles rookie with that stat line since Don Johnson in 1953. Eagles coach Doug Pederson, asked this week about Clement in the red zone, gave a similar answer about “want-to.” He added that Clement is “a very violent, aggressive runner, and just loves ball. Any time he gets in there, he just goes 100 miles an hour, and he is a smart guy. He’s coachable. And he does exactly what you ask him to do.” Five touchdowns in 51 touches (48 runs, three catches) is a lot. Clement has played only 19 percent of the Eagles’ offensive snaps so far, but his total has gone up steadily over the last month – from 10 to 12 to 19 to 28.