SAN FRANCISCO (AP) — Just two months ago, the San Francisco 49ers grabbed control of the NFC West from the Arizona Cardinals behind Alex Smith’s near perfect performance on a Monday night in the desert.

Oh, how much has changed since.

The slow and steady Smith has been replaced by Colin Kaepernick, a high-risk, high-reward quarterback who coach Jim Harbaugh is counting on to lead the suddenly fragile 49ers (10-4-1) deep into the playoffs. The Cardinals (5-10) are on their fourth starting quarterback in Brian Hoyer and have lost 10 of 11 games to put coach Ken Whisenhunt’s job in jeopardy.

One team is headed to the postseason, the other for a head start on the NFL draft. The only question left is where each will be seeded for their final destinations.

San Francisco can clinch its second straight division title and keep its shot at a first-round bye alive in Sunday’s regular-season finale against Arizona at Candlestick Park. The once promising Cardinals are 60 minutes away beginning another offseason of upheaval.

“Sometimes in a game like this, anything goes,” Harbaugh said. “Their mindset will be to win the game. So you have to be ready. You have to be alert for just about anything.”

At the very least, last week should’ve reminded the 49ers of that much.

San Francisco’s 42-13 shellacking in Seattle handed Harbaugh the worst loss of his NFL coaching career. It showed how flimsy the 49ers and their second-ranked defense can be without Justin Smith, the versatile lineman whose streak of 185 games ended with what the team has called an elbow injury. Smith is not expected to play against Arizona and his status for the playoffs remains murky.

Harbaugh has shown the ability to rebound his team quickly. The 49ers are 7-0 after a loss or tie in his tenure, and he’ll need to rally his players again at the most important time.

The 49ers can still secure the No. 2 playoff seed — and the first-round bye that comes with it — with a win coupled with a Green Bay loss at Minnesota. If they lose and Seattle (10-5) wins at home against St. Louis, the Seahawks will steal the NFC West and send San Francisco on the road for the first round.

“It’s for the NFC West,” 49ers running back Frank Gore said. “That was our goal coming into this season — to win the NFC West. We get a chance to do that this Sunday. That’s what we want. We’re upset about last week. We’ve got to win.”

Last week was a 42-13 loss at Seattle. That alone should provide an attitude strong enough to keep San Francisco sharp.

Hoyer is making his first NFL start, less than three weeks after the Cardinals claimed him off waivers from Pittsburgh. The former Michigan quarterback spent three seasons as a backup to Tom Brady in New England, was out of a job for most of the year and then relieved Ryan Lindley in Arizona’s 28-13 loss to Chicago last week. Hoyer has appeared in 14 NFL games, including 13 with the Patriots. He completed 11 of 19 passes for 105 yards with one interception against the Bears while operating an offense that ranks last in the league.

“It’s a crazy business, but to me it’s the best job in the world,” Hoyer said.

Quarterback will be near the top of Arizona’s to-do list when the season is over, although just who will be in charge of that decision is uncertain.

Cardinals President Michael Bidwill said he will assess the situation after the final game to determine if Whisenhunt comes back for the last year of his contract. General manager Rod Graves also might be gone. If Whisenhunt stays, some of his assistants almost certainly won’t.

“It’s been tough,” Whisenhunt said. “This business is about winning games. And when you don’t do that, it makes everything more difficult.”

Arizona started the season with four straight wins and still had a chance to pull even with San Francisco after dropping three straight in October. Then the 49ers routed the Cardinals 24-3 on Oct. 29, a game Smith completed 18 of 19 passes for 232 yards and three touchdowns. He also had a 157.1 rating in a performance that earned NFC offensive player of the week honors.

Smith suffered a concussion the next game against St. Louis, Kaepernick took over and had his own Monday night breakout in a home win against Chicago. Kaepernick, a second-round pick out of Nevada last year with a strong arm and fast feet, is 4-2 as a starter.

The sometimes spectacular, sometimes shaky quarterback will lead an offense that has been depleted by season-ending injuries to wide receivers Mario Manningham and Kyle Williams. Tight end Vernon Davis also must clear the league’s NFL concussion protocol after getting knocked off his feet by Seattle’s Kam Chancellor last week.

The absence of so many key targets will put even more pressure on Kaepernick in a quarterback debate that continues to rage on — maybe this week more than most.

“I just think that Alex worked for seven years to get to the position he was in,” said Cardinals guard Adam Snyder, who spent seven years playing alongside Smith in San Francisco. “He was 19-5 (the past two seasons) and had the best QB rating in the league and was doing his job to win games, you know?

“I don’t know. It was surprising to me. But, hey, they get paid to make those decisions, and that’s the decision they went with.”