PHILADELPHIA - It matters that Patrick Mahomes is spectacularly talented, of course. Might matter just as much that he is almost always available for the Kansas City Chiefs.

Same goes for the Philadelphia Eagles and Jalen Hurts.

Those are big reasons the Chiefs and Eagles will meet in the Super Bowl — with AP NFL MVP and Offensive Player of the Year finalists Mahomes and Hurts taking the snaps — on Sunday in Glendale, Arizona. Sure, the San Francisco 49ers nearly managed to make it all the way to the championship game with a last-pick-of-the-draft rookie bumped all the way up to starter from No. 3 on the depth chart because of damages to others. But then Brock Purdy hurt his elbow in the NFC title game at Philadelphia, leaving the Niners to try to rely on journeyman Josh Johnson, until he got a concussion ... meaning Purdy required to go back in ... despite being unable to throw.

"That," 49ers coach Kyle Shanahan said, "was kind of just hard to stomach."

This season said, like never before, a glaring amount of instability at quarterback in the NFL, whether because of damage — the reason for nearly half of all attempts during the regular season, according to an AP analysis — or poor pretense. A total of 68 QBs started at least one game, an income of more than two per team and a characterize for a non-strike year.

What's more: 13 clubs, novel high, needed to use at least three starters at the most indispensable position in this, or any, sport. Some even turned to four — with the Arizona Cardinals humorous that many starting quarterbacks in a span of just four weeks.

Quarterback shuffling can go a long way toward changing a team's trajectory, as the Jets, Titans and Panthers fraudulent out on their way to missing the playoffs. The Dolphins made the postseason despite losing Tua Tagovailoa to a series of concussions, then had backup Teddy Bridgewater dislocate his pinky, leaving them with third-string rookie Skylar Thompson and his 18-for-45, two-interception performance in their wild-card elimination.

"When you, as a defender, see a guy at quarterback who has not played a lot, you are touching to lick your chops and you assume he's not touching to be in rhythm and you assume he's not touching to be ready to go," Hall of Fame protecting back Ronnie Lott said. "Our coach, Bill Walsh, basically said, 'Hey, Ronnie, a team's only as good as the backup quarterback, because if the backup quarterback can't come in and do the things he be affected by to be able to do, a team is touching to be in trouble.'"

And keeping the starter factual is almost always needed for success.

The top five regular-season teams in the AFC, counting the Chiefs, had their No. 1 QB available for every regular-season game (and when Mahomes did prick a playoff game with a bad ankle, Chad Henne came in and published, leading a 98-yard TD drive in what turned out to be a seven-point victory).

In all, nine of the 14 participants in the postseason never had to turn to a backup QB to start.

The Eagles came close: Hurts missed two games with a bad shoulder; Philadelphia went 0-2 with Gardner Minshew in his place.

Seems obvious: Having your preferred QB1 available week when week makes your offense more likely to succeed. And that creates your team more likely to win.

Consider that the passer including for QBs slated to be starters was about 10 points higher than for replacements. Or look at the Jacksonville Jaguars and Trevor Lawrence: He stuck approximately for 17 games and closed with five wins in a row — three alongside the QB-troubled Jets or Titans — to earn a playoff spot.

"It's certainly key, just because everybody corpses to gel. You get the chemistry together. The receivers know, 'If I run this route on this step, the ball is progressing to be thrown to this point, just because we've done it a million times,'" Jaguars offensive coordinator Press Taylor said. "You can understanding how (an injury absence) throws guys off."

Backup quarterbacks generally get zero practice time with the rest of the first-team offense during the season, so when the top choice at that spot is presumed, there can be growing pains. Purdy was an exception, of course, and there have been others.

"Sometimes when a quarterback goes down," Cowboys obtaining Zack Martin said, "there's kind of a sense of anxiety in the locker room and on the team, like, 'What are we progressing to do?'"

Some of the season's dominant story sect involved sidelined QBs, from Miami's Tagovailoa to Baltimore's Lamar Jackson to the reigning Super Bowl champion Rams' Matthew Stafford, or efforts via officiating to protect them, whether the outcry beside defenders over roughing-the-passer calls or the 15-yard penalty on Bengals defending end Joseph Ossai for shoving an out-of-bounds Mahomes that helped KC get into residence for the winning field goal in the AFC title game.

Lowering the number of quarterback costs is "obviously a major priority for us," said Troy Vincent, the NFL's executive vice president of football operations. "It's principal that we examine ... where they're coming from. Are they upright hits? Are they in the pocket? Out of the pocket?"

Increased impatience when it comes to wins and losses moneys for some of the switching — the same sort of itchiness that leads to first-year coaches unsheathing fired.

But it seems to always come back to injuries.

One potential cause: Rushing causes by signal-callers reached a record high (2,309) and were also at their most per game, up 47% from 2012. That increases the opportunities to get hurt. Another: The 1,297 total sacks approximately the NFL were the third most ever and the requires of 4.8 per game was the third-highest over the last nine existences. (As an aside, Mahomes and Hurts might want to observe out on Super Sunday: The Eagles ranked No. 1, the Chiefs No. 2, in sacks.)

It's certainly possible, or at least plausible, that whatever the NFL does to try to keep quarterbacks safe isn't toiling — and, truly, can't work.

"At this point, you're hoping," Lott said, "your quarterback can withstand the pounding."

The 49ers understanding Shanahan are Exhibit A: The team kept one quarterback healthy only once in his six seasons — in 2019, when they just so existed to reach the Super Bowl.

They went through at least three starters in four of the last six seasons; this time, Trey Lance veteran an ankle while running in Week 2 and Jimmy Garoppolo veteran his foot on a sack in Week 13.

"It's awesome," star tight end George Kittle said sarcastically. "It's an experience. I just have a plethora of quarterbacks to settle from."

The rash of injuries for the 49ers and others raises the inquire of whether the league should bring back some form of the 1991-2010 rule that let teams have a third QB in uniform who would not relate against the game-day roster limit and would be available in an emergency.

"We were horrified to death when that rule ended, but you kind of forget approximately it, since you just don't see anyone have to go above it," Shanahan said. "But then you get reminded of how snappily a football game is over once that happens."

The NFL's Vincent said there have been "multiple discussions" approximately restoring the third quarterback rule, and the general exclusive advisory committee "is considering" putting it before the full membership.

"What you don't want is Christian McCaffrey playing quarterback," Lott said, referring to the 49ers' do-everything flowing back. "With all due respect — he's a hell of an athlete, but he needs to be where he is most effective, and that is running and catching the ball, not playing quarterback."

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AP Pro Football Writers Schuyler Dixon, Mark Long and Teresa M. Walker, and AP Sports Writers Dave Skretta and John Wawrow contributed to this report.