Through four games, Anquan Boldin has registered 15 catches for 124 yards and one touchdown.
Torrey Smith, who signed a five-year, $40 million contract this offseason, has caught nine passes for 185 yards and one score.
During Sunday's loss to the Packers, both receivers showed visible frustration with Colin Kaepernick and the 49ers' offense.
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"There is evidence that he (Kaepernick) has lost his receiver corps," 49ers radio analyst Tim Ryan said on KNBR 680-AM on Tuesday morning. "The frustration is they're not winning and the quarterback's not delivering the mail like he's capable of doing.
"So it appears, from the outside looking in, that he's lost his receivers, but there's still leadership and those are good men, and they've played a lot of good football ... they've got to figure out how to re-kindle any kind of relationship or a chemistry with the quarterback -- whether that's off the field, and spending more time with him and trying to figure this thing out collectively."
Why did Boldin and Smith exhibit poor body language? Let's explore.
On the 49ers' second offensive play from scrimmage, Kaepernick missed an open Boldin.
Ryan's analysis during the game: "That had to come out of his hand funny. Boldin was open ... all the defenders were behind him. That should be an easy throw for Colin. Geep Chryst trying to give him a layup."
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The 49ers' second possession ended on a Kaepernick incompletion, that was intended for Smith but sailed several yards out of bounds.
Play-by-play man Ted Robinson's description: "And Torrey Smith very unhappy as he comes off the field, takes his helmet off and sits right down on the bench."
Ryan's analysis during the game: "He did not give Torrey Smith a chance there ... you throw the back shoulder throw. That's what Torrey was expecting and could have made a play on it. Not even close, as it looked like Colin just threw it away to get it out of bounds."
On the 49ers' first possession of the second half, offensive coordinator Geep Chryst called a run-play up in the middle on 3rd and 11. Reggie Bush was stuffed for no gain and the 49ers punted.
Boldin wasn't happy with the play selection.
With 9:24 remaining in the fourth quarter, Kaepernick threw deep for Smith but he had no chance to make a catch.
Ryan's analysis during the game: "You gotta give the receiver a chance. He's (Smith) got Sam Shields in a trail position ... Colin gave him no chance with the ball location..."
On the very next play, Kaepernick didn't anticipate Smith breaking open and took a sack.
On the following snap, Kaepernick lobbed a pass deep down the field for Boldin. It was intercepted.
Ryan's analysis during the game: "Tactically, it could have been a touchdown by Anquan Boldin. He is wide open. Wide open. If that ball comes out early and lets Anquan Boldin run to the numbers. And there was not a lot of pressure. Colin moving around the in pocket, never saw it, tried to throw it late, and Shields gets the interception."
Following the loss, Kaepernick acknowledged Boldin and Smith's frustration.
San Francisco 49ers
[REWIND: Frustrated Niners: Kaepernick overcorrects, takes no chances]
“They’re playmakers for this team,” Kaepernick said. “They want to contribute. They want to have an impact. And we weren’t able to get the ball to them and allow them to have that impact until later in the game. So I understand the frustration, yes. But it’s a team game. They want to win. I understand that...
"We have to be able to get the ball into our playmakers’ hands as soon as we can. Ultimately, this offense is a team. We’re working as hard as we can to make sure we’re doing things right and on the right track.”
On Monday, Smith declared that he and Boldin are on the same page as Kaepernick, but it has to translate to the field on gameday.
“That has to change or we’re not going anywhere,” Smith said. “We have to get that right between the quarterbacks and the passing game, in general. If you can’t pass the ball in 2015, you’re in trouble.
“Certain routes, you don’t have to have all the time in the world. There are things we can do to make it happen, but we just have to be confident at it and get some rhythm going.”
Despite the fact that Kaepernick boasts the third worst passer rating in the NFL, Ryan isn't ready to pull the plug.
He's hopeful something will click and that critics must take into account Kaepernick's full body of work.
"He (Kaepernick) is not a rookie who was just handed the job," Ryan said "He has earned the right to work through this, in my opinion. Human nature is to get frustrated and point the finger, and to fracture and go the other way.
"But this next five games, they've got to get it together or the long-term future of Colin Kaepernick as the franchise quarterback, and the guy you want leading your team in the hardest position in sport, that's gonna be a challenge to keep that going."