Lamar Miller has become the Miami Dolphins' go-to running back by default.

Two weeks into the season, free-agent pickup and expected starter Knowshon Moreno dislocated his elbow and missed two games. Six weeks into the season, Moreno tore his ACL and was done for 2014. Miller was thrust into the spotlight.

In his first two years, Miller failed to meet expectations after being selected in the fourth round of the 2012 NFL Draft by the Dolphins. He was a 21-year-old struggling with the playbook at the time. He carried the rock only 277 times in the two years combined.

However, with Moreno out of the lineup he had to step up and help Ryan Tannehill, the franchise quarterback, keep the offense moving.

Through seven weeks, Miller has responded. He’s averaging 4.8 yards per carry and is carrying the ball two times per game more than he did in 2013. He’s also doubled his touchdown total from last season to four. He’s still sometimes inconsistent, however, missing alleys when pressured into making a quick decision.

In Week 6 against the Green Bay Packers, Miller was lined up in a shotgun formation, offset six yards from the line of scrimmage. The play was a zone stretch. A back-side tight end would loop in front of Miller and around the line to kick the cornerback outside, potentially creating a cutback lane.

Behind his facemask, Miller looked left and right, seemingly paranoid before the snap. He envisioned his cuts, hoping to avoid his tendency to sometimes cut too much in fear of losing yardage. The big plays were always right in front of him, as long as he was able to navigate through the forest of linemen and linebackers.

Miller took the handoff to his left and saw two potential alleys: between the left guard and center or his right guard and tackle. Unexpectedly, his right guard was manhandled. He was pushed into the backfield, restricting Miller’s breathing room and speeding up his decision making.

The cutback lane was nonexistent because the tight end took too narrow of an angle and missed the cornerback. Miller’s time to decide suddenly sped up, and without an idea of where to go, he played hopscotch.

He bounced right when he could have gone left, only to see it too late. When he tried to cut left, he ran into his center’s rear. He then bounced right again, finding room to run before the cornerback came from behind him and wrapped his arms around his waist for a 4-yard gain.

When his lanes are defined, Miller’s more decisive and slithers through alleys like a snake. He keeps his pads low and his cuts are smooth, bending and cutting corners like he’s in a light jogging session. It’s effortless. If he runs into a bad spot, he quickly bounces out of it and into the open field, like he did against the Kansas City Chiefs in Week 3.

Late in the fourth quarter, Miller was offset in shotgun again. It was first-and-10 and the call was a zone stretch.

The back-side tight end again whipped around the line and, this time, pivotally blocked the end man, an outside linebacker. Miller ran left and up the middle, but there weren’t many openings there. When an inside linebacker shot through the A-gap in between the right guard and center, there weren’t any. But because the tight end blocked the linebacker, there was an escape route through the cutback lane.

Miller swayed his shoulders and planted off of his left foot to shoot outside. A jump-cut burst him into the open field, where he ran right, further outside, trying to bait the run-filling safety so he could shackle him to the ground and run around him. That didn’t work. Miller cut inside, dropped his left shoulder and collided with the cornerback, sliding over him and avoiding a thumping as he dove forward for a 9-yard gain.

Miller rarely punishes defensive backs, usually falling at first contact. It’s one of the oddities about him. He’s 224 pounds but runs like he’s 195. What he does, instead, is burst by defenders, picking up yardage in chunks with his quick feet. In the same game against Chiefs, he showed that off with a 20-yard rip that was arguably his best run of 2014.

The tight end motioned from the right end of the trenches to the left on second-and-10. He set up a back-side block, the same one from the previous plays, that kicked out the outside linebacker once again. The right tackle and guard combination blocked the near defensive tackle.

Miller ran left and stopped on his left foot, then his right. He looked outside, in between the tackle and tight end, where an alley was forming, and waited for the blocks to materialize before he stuck his foot in the ground and burst forward.

He accelerated, turned outside, then back inside and squared his shoulders, speeding downhill as the white towel on his hip jumped around like it was a fire in the wind. He broke one ankle tackle and lowered his shoulder as another defender came in. He avoided the big hit, falling over and picking up 20 yards.

As Miller gets more carries, he’ll blossom into a more complete running back. He has the talent to be one of the league’s best, with stop-start ability like Edgerrin James once had. That’s what the Dolphins expected when they took him No. 97 overall three years ago and that investment is finally paying off.