SANTA CLARA, Calif. -- The opening drive of Sunday's game against the Arizona Cardinals couldn't have gone much better for San Francisco 49ers quarterback C.J. Beathard.

Taking advantage of Arizona's blitz-heavy approach, Niners coach Kyle Shanahan dialed up a series of short, quick throws intended to protect Beathard, helping him get the ball out quickly and allowing room for pass-catchers to run.

Sure enough, Beathard completed his first five pass attempts for 59 yards, including a 5-yard touchdown on a left-handed shovel pass to running back Matt Breida. But Beathard's promising start came to a quick end as the Cardinals began taking away many of those short passes either with tweaks in coverage, getting their arms up to deflect passes or a combination.

"There's only so many screens you can call," Shanahan said. "I think we hit our quota."

Once the Niners moved away from screens, the onus shifted to Beathard standing tall in the pocket, identifying oncoming pressure, getting through his progressions and delivering accurate passes while protecting the ball.

As had been the case in each of the previous seven games in which he'd played the majority of the snaps, the first part of that plan came easily. Beathard was his usual, fearless self in the pocket. But the rest of the equation mirrored other rough moments in Beathard's young career.

By the time the disappointing 28-18 loss was over, Beathard had posted career highs in completions (34), attempts (54) and passing yards (349). Despite those numbers, Beathard's performance was marred by another career-high: turnovers.

In a game the Niners lost almost solely because of their minus-five turnover margin, Beathard had a hand in four of them, including two interceptions and two fumbles lost. Those giveaways led to 14 of Arizona's 28 points.

"You can't win ballgames turning the ball over five times," Beathard said. "I feel like we played well in all the other aspects except for turnovers. [I've] just got to take better care of the ball."

In the eight games in which Beathard has attempted at least one pass, he's flashed potential with his ability to extend plays and take big hits while delivering the ball. Much of that enthusiasm has also been tempered by turnover issues. In those games, Beathard has fumbled six times, losing four, and thrown 10 interceptions. He's had at least one giveaway in every game and has had two or more in half of them.

Now in his second run as the Niners starter, Beathard says things have slowed down for him and he's seeing things better than he did as a rookie. That wasn't as evident against the Cardinals as it was in Week 4 against the Chargers.

"I know yesterday wasn't a great day in that area," Shanahan said. "I think it was a lot easier for everyone to see versus Los Angeles. I thought yesterday we got caught on the pocket a number of times. That didn't all have to do with C.J. There's times that it did. There's times that they had some blitzes where he had to get rid of it. There's times where we didn't get open very well. By no means was C.J. perfect, but it was not all his responsibility."

Of course, the tape of Sunday's loss shows that Beathard wasn't entirely at fault for the turnovers, either.

Beathard's first interception was a bit high but bounced off receiver Pierre Garcon's hands. It wouldn't have been an easy catch, but Garcon has made more difficult plays (including one in Sunday's game) during his career.

Left tackle Joe Staley also took blame for selling a run block too hard on a play-action pass that resulted in Beathard's first fumble. Beathard did step up in the pocket but appeared to have a bit more room to help avoid pass-rusher Chandler Jones, who also deserves credit for the play.

After the game, multiple Niners talked about the need to help make Beathard's life less difficult.

"We keep talking about how tough C.J. is and he's one of the toughest guys I know, one of the toughest guys I've played with," fullback Kyle Juszczyk said. "Your quarterback, that shouldn't be his No. 1 attribute is being tough. He shouldn't have to do that. We should make things easier for him."

As of now, Beathard is in no danger of losing his starting job, barring some sort of injury. The 49ers want to continue to develop him and give him opportunities to get better over the season's final 11 weeks.

On Monday, Shanahan said the Niners will keep evaluating options to bring in a third quarterback but that would depend on other injury situations and how those could affect the roster. Still, there's no indication that any quarterback brought in would be anything more than a No. 3 behind Beathard and Nick Mullens, at least for now.

For that to continue to be the case, though, Beathard must find a way to cut down on the mistakes and ensure that as many possessions as possible end with some sort of kick.

"The bottom line is you can't lose the ball," Shanahan said. "Whether you get hit, whether someone's not open, sometimes you need to get rid of it, sometimes you need to take sacks. But the worst-case scenario, we plan on ending that series with the ball in our hand and that's something he's got to do a better job of."