Darren Sproles has spent his career watching players who were bigger or not as talented pass him over. The Eagles went out and signed two running backs this offseason that Chip Kelly hailed partly because of their size, and then slotted them ahead of Sproles despite his rushing production in 2014.

After Kelly signed DeMarco Murray and Ryan Mathews in March, he said that he planned to utilize Sproles more in the passing game. While his catches per game have increased, his yards per catch have dropped. That plan, for the most part, hasn't worked.

Sproles is still playing around the same percentage of snaps, but it's not enough for his liking. Against the Dolphins, for instance, Sproles didn't play an offensive snap until the second quarter. Overall, he played only 17 of 96 snaps, and that number would have been lower had Mathews not left with a concussion.

"Things get kind of frustrating. You know what I'm saying?" Sproles said this week. "You're standing on the sidelines. It's kind of frustrating. But what can you do?"

It's a numbers game for the 32-year old. He's the third-string running back and the second-string slot receiver behind Jordan Matthews. Sproles still returns punts - he's third in the NFL with 12.5 yards per return - but his touches in his last two seasons with the Eagles haven't been near the amount he had with the Saints.

Sproles had around the same per-yard production last season as he had in New Orleans, but his averages are significantly down this year. Is he losing a step or hasn't Kelly done a good enough job taking advantage of his skill set?

"I'm not really on the field. But I don't get into that," Sproles said when asked if he thought he was being used properly. "If they're going to put me on the field, they're going to put me in. If they're not, they're not. You know what I'm saying? If they do put me in, I just try to make the best of it."

Sproles is playing 31 percent of offensive snaps this season. He played 31 percent in 15 games last season. He's averaging more rushes per game (4.3 vs. 3.8) and more catches per game (3.2 vs. 2.7), but his production has declined in both the run (3.7 yards per rush vs. 5.8 last season) and the pass (6.9 yards vs. 9.7).

But would his statistics climb with more opportunities? If he has slowed, the decline is so small that it is unnoticeable. The same cannot be said of receivers Miles Austin and Riley Cooper. And yet, they have played much more - Austin at 52 percent and Cooper at 46 percent - than Sproles.

They play different positions, of course. And the offense probably has been built too heavy inside at running back, tight end and in the slot. But isn't it Kelly's responsibility to find a way to put his best pieces on the field together?

Is there any justifiable argument that can be made for Austin, who will make $2.2 million this year, playing more than Sproles, who makes $4.1 million?

Sproles wasn't a focal point of the offense on Sunday because Kelly wanted to employ his two-tight end package. There isn't a slot receiver in that grouping, and unless he's the lone running back, Sproles isn't on the field.

The strategy worked early on. The Eagles scored two touchdowns on their first two series and drove to the 12-yard on their third before missing a field goal. But as the game wore on, the Dolphins had more success countering the Eagles in the two-tight end set.

Sproles never got going. He had just three carries for no yards. He had five catches for 24 yards, but most were of the check-down variety. He has decreasingly been the first or second read on plays.

Kelly had good intentions early on. Sproles caught several passes out of the slot in the preseason, including a 33-yard grab against the Packers that exploited mismatches against linebackers. Kelly had him in the backfield with Mathews several times against the Cowboys in September, but two passes and a carry out of that formation netted little.

"A lot of times when he goes in there, he gets two people covering him," Kelly said. "So they're not mismatches; it's an advantage for the defense, so we have to go away from him."

Kelly has tried other ways to get Sproles the ball. He called two jet sweeps against the Redskins, but both were diagnosed before the snap by the defense. He has split him out as a wing a bunch of times and in Dallas earlier this month tried to free him with a rub route. But the Cowboys disrupted the timing and Bradford's pass was off.

There could be an assortment of reasons why the Saints had more success utilizing Sproles as a pass catcher even though he played about the same amount of time. Having Drew Brees at quarterback is probably one. But Sproles averaged 5.2 catches and 45.0 receiving yards per game in New Orleans and has averaged only 2.9 catches and 24.4 yards in Philly.

He has become less of a weapon in the passing game and he's third on the running back depth chart.

"I'm not getting enough chances," Sproles said. "They got me more in there to run routes. DeMarco and Ryan get the bulk of the carries. . . . To get in a rhythm you need more touches. That's for any kind of player."

Sproles should get more against the Buccaneers on Sunday. Mathews is unlikely to play.