The Dolphins, who have churned through a dozen or so receivers since training camp, added another one Monday when they were awarded Armon Binns off waivers from Cincinnati.

Undrafted out of the University of Cincinnati in 2011, Binns caught 17 passes for 210 yards and a touchdown this season but was inactive for four of the Bengals’ previous six games. Binns was released by the Bengals on Saturday, and Cincinnati had hoped to sign him to the practice squad.

The Dolphins released cornerback Michael Coe to make room on the roster. Binns joins Brian Hartline, Davone Bess, Rishard Matthews and Marlon Moore as receivers on Miami’s 53-man roster.

Meanwhile, Dolphins coach Joe Philbin acknowledged Monday that the receivers’ inability to create consistent separation was an issue late in the loss to the 49ers.

Philbin admitted that when asked how Ryan Tannehill played.

“Ryan played better in the first half,” he said. “At the end of the game, statistically, he didn’t perform as well as he would like. There were a lot of factors that contributed to that. It wasn’t just him.

“There wasn’t as much separation in the route running that we need. It wasn’t like there were wide-open guys that we’re just flat out missing. And a couple times, even though we weren’t sacked on some of those, the protection — the depth and width of the pocket — was compromised.”

This and that

• Offensive coordinator Mike Sherman said the team’s inability to make enough plays offensively late in games is “expletive frustrating.” (Yes, he used the word expletive.)

“We feel like we’re close but we’re not close enough,” he said. “I really feel for this group of guys. They are one of the hardest working groups I’ve been around. They were very disappointed after the game. You could hear a pin drop on the bus and plane. They’re giving us everything they have.”

• With the playoffs highly unlikely, Philbin was asked if a case could be made to give more playing to young players, especially tight end Michael Egnew — to see what the Dolphins have going into the offseason. Philbin suggested he’s disinclined to do that.

Here’s how he answered: “I told the team in the locker room: … ‘We have a game on Dec. 16 at 1 p.m. against Jacksonville. They’re going to show up in this building to prepare to win this game against Jacksonville. That’s all I’m concerned about right now.”

• Philbin was asked how much of the offensive problems are correctable and how much comes down to talent. “It’s correctable,” he insisted. “There were plays to be made on both sides of the ball at the end of the game that we didn’t do.”

• Asked if losing five out of their past six games suggests that improvement is not being made, Philbin said: “There will be a time and place to look at the whole thing. But certainly the outcomes have not been what we want.”

• Philbin said he would not comment about — and said he did not see — punter Brandon Fields push Jonathan Freeny after Freeny’s ridiculous special-teams mistake in which he strolled back and touched the goal-line, thus negating what should have been a downed punt at the 49ers’ 3.

• Linebacker Jason Trusnik — and to a lesser extent, Jared Odrick — appeared primarily to blame on Colin Kaepernick’s 50-yard touchdown run, but defensive coordinator Kevin Coyle said: “It wasn’t just one or two guys. …

I thought they were just going to run the ball inside and be content with trying to punt and play defense.”

• Linebacker Koa Misi’s ankle injury puts his status in serious doubt for Sunday’s home game against Jacksonville.

• The Dolphins have forced only one turnover in the past six games (a Reshad Jones interception), and Coyle said: “It’s hard to figure. We’ve created 17 fumbles and only gotten three of them. It seems we’re right there.”