Chip Kelly was asked Monday on KNBR’s “Murph and Mac Show” what quarterback would start for the 49ers on Sunday in Buffalo.

“Which one of you guys are available?” Kelly asked the middle-aged radio hosts.

No, things haven’t become quite that desperate for the 49ers, who are 1-4 with quarterback Blaine Gabbert, the struggling starter who is no longer receiving public support from his head coach.

Kelly has left the door open for Colin Kaepernick to replace Gabbert since a 33-21 loss to the Cardinals on Thursday, but he said which quarterback will start against the Bills remains an open question.

“We’ll get together as a staff today and look at our game plan in terms of moving forward and what we’re going to everywhere,” Kelly said. “… We’ve got to evaluate everything. Part of it is what kind of game plan are we going to put together for the Bills.”

There is widespread speculation that Kelly is waiting for Kaepernick to sign his restructured contract before demoting Gabbert, who ranks 27th in the NFL in completion percentage (58.0), 30th in passer rating (69.6) and 31st in yards per attempt (5.9). On Friday, the NFL Network first reported that the 49ers were working on a restructured contract that would eliminate the injury guarantee that is tied to Kaepernick’s $14.5 million salary in 2017.

Kelly, however, insisted Kaepernick’s contract status has no bearing on his quarterback decision. He said he’s never been told to keep Kaepernick sidelined because of the potential financial ramifications.

Kelly, again, noted Kaepernick played in a 28-0 season-opening win over the Rams. It was noted to Kelly that the chances of Kaepernick getting hurt in Week 1 were microscopic: Kaepernick handed off to running back Mike Davis each of his three snaps with less than three minutes left in the game.

“My only point is I’ve never been told not to put him in a game,” Kelly said. “So if I was ever told to not put him in a game that conspiracy theory should be done because he’s been in a game. That’s the only reason I bring that up. If he hadn’t played a snap, then people could say ‘Well, you’ve been told not put him in a game.’

“I’ve never been told, implied -- whatever word you want to use -- on who to play and who not to play. … Whether it’s garbage time or whatever, you’re still susceptible to injury.”

On Friday, less than 24 hours after Kelly made it clear he was open to a quarterback change, it was reported 49ers working on a restructured deal with Kaepernick. It suggests the 49ers were willing to assume a certain level of risk with Kaepernick: That is, he could have been forced into any of the first five regular-season games if Gabbert had been injured.

However, with the chances of him replacing Gabbert and starting the final 11 games becoming more likely, they want to eliminate the risk completely.

There’s no guarantee Kaepernick will provide a boost for an offense that ranks 31st in the NFL and has yet to surpass 320 yards in five straight games for the first time since 2009.

In the quarterbacks’ last 13 starts, Gabbert has a slightly better passer rating (80.4 to 76.2) and completion percentage (61.3 to 58.6) than Kaepernick. Still, Gabbert’s performance this season begs for the 49ers to consider another option.

Kelly acknowledged the 49ers need to get outside wide receivers Torrey Smith and Quinton Patton more involved. The duo has combined for 21 catches for 228 yards and one touchdown. They have been targeted with 43 passes, two fewer than slot receiver Jeremy Kerley. On Thursday, Gabbert targeted Kerley and running back Carlos Hyde with 19 of his 31 passes, while throwing three to Smith and Patton.

“We need to get more contribution and get our other receivers involved to spread the ball around,” Kelly said. “We need to get our outside receivers and tight end involved also, so there are three other guys out there … that we need to get involved and get the ball in their hands.”

Eric Branch is a San Francisco Chronicle staff writer. Email: ebranch@sfchronicle.com. Twitter: @Eric_Branch