The San Francisco 49ers are looking to improve to 8-0 when they host the Arizona Cardinals on Thursday, but they may not be as healthy as they initially hoped.

The 49ers were bullish that offensive tackle Joe Staley would return from his broken fibula this week, but it doesn't look like he is ready, as Staley is listed as doubtful for San Francisco's Week 9 tilt.

Staley suffered his injury back in mid-September and has missed the last five games as a result.

“Without us having a full-speed practice, it’s going to be kind of tough to simulate some stuff here in this day and a half,” said 49ers head coach Kyle Shanahan, according to Chris Biderman of The Sacramento Bee. “So we’ll see how he feels. I put him more in ‘doubtful’ whenever I have to do that, but there’s still a chance.”

In addition, Niners running back Matt Breida is listed as questionable due to an ankle injury.

Breida has been a key cog in what has been a terrific rushing attack for San Francisco this season, as he has rushed for 446 yards and a touchdown while averaging a hefty 5.3 yards per carry. He has struggled over the past few weeks, however, logging 2.8, 4.4 and 3.2 yards per attempt, respectively, in each of the 49ers' last three games.

Now in his third season, Breida is coming off of a breakout 2018 campaign in which he totaled 814 yards and three touchdowns on the ground, registering 5.3 yards per carry and catching 27 passes for 261 yards and a couple of scores in the process.