Mike McCarthy wouldn’t let himself qualify the Packers’ early-season success as a "fast start" until getting to 4-0. With a win Sunday at San Francisco, McCarthy would be able to feel good about the way his team got through the first quarter of the season.

Here are five things to watch in Sunday’s Packers-49ers game.

1. Green Bay’s defense not letting Colin Kaepernick look like 2012-13 version of himself

Remember when Kaepernick was one of the NFL’s best young quarterbacks? The Packers sure played a role in that during the 2012 and 2013 seasons.

San Francisco handed Green Bay a loss to begin and end the Packers’ season in both of those years. Kaepernick didn’t start in Week 1 of the 2012 season (Alex Smith was still the starter), but he did come in and rush once for 17 yards. But in the three most recent games, Kaepernick threw a combined six touchdowns and two interceptions, while also rushing for 301 yards.

Now, Kaepernick is coming off a game (a 47-7 loss at Arizona) in which he threw four interceptions. It’s gotten to the point that 49ers head coach Jim Tomsula is being asked why Kaepernick is even the starting quarterback.

Two weeks ago, Green Bay allowed Russell Wilson to rush for 78 yards on 10 carries. That’s still well short of Kaepernick’s 181-yard effort against the Packers a few years ago, but a 7.8-yard per-carry average is still too many rushing yards allowed to a quarterback.

It will be important for Green Bay to prove that it can stop Kaepernick, whose confidence has likely never been lower.

2. Aaron Rodgers, post-Michael Jordan comparisons

The comparison makes sense, even if it does make Rodgers feel a bit uncomfortable.

"It’s like watching Michael Jordan in his prime," wide receiver James Jones said this week. "Every time you go out there, the dude does something special. I’ve been saying these first three weeks: We’re all witnessing something special. We may not realize it until he’s done and retired, how great he was. But he’s a special QB."

Rodgers responded: "I’m not worthy of that comparison. ... It’s a nice comparison. I’m just trying to be a guy they can count on every week. I know my play is very important to this team, but it takes all the guys that dress playing well for us to win."

Rodgers’ 135.4 passer rating is by far the best in the NFL. He’s thrown 10 touchdowns, zero interceptions and has made defenses look foolish with his ability to draw offside and 12-men-on-the-field penalties.

That’s Jordan-esque dominance. But now that the comparison has been made by Rodgers’ own teammates, it will be interesting to see what type of performance he puts together.

3. More chances for young WRs and TEs

The Packers already know they’ll be without wide receiver Jordy Nelson (out for the season) and tight end Andrew Quarless (placed on injured reserve with designation to return in eight weeks). Green Bay could also enter Sunday not having wide receiver Davante Adams, who didn’t participate in either Wednesday or Thursday’s practices after having left the Monday night game after just three snaps.

Rodgers still has a few trusted options to throw to, namely Randall Cobb and James Jones, both of whom have four touchdown catches this season. Richard Rodgers has proven to be a dependable target as well, but the second-year tight end has a modest 65 yards and one touchdown through three games.

Wide receivers Ty Montgomery and Jeff Janis will likely see a lot of action, as could tight end Kennard Backman. If San Francisco effectively game-plans to take away at least one of Rodgers’ preferred targets, Montgomery, Janis and Backman need to show early signs of having their quarterback’s trust.

4. Packers’ chance for the trifecta in stopping starting RBs

Marshawn Lynch and Jamaal Charles combined for 90 rushing yards on 26 carries over the past two games. Yes, Charles scored three touchdowns, but from a non-fantasy-football perspective, he was held mostly in check.

San Francisco’s second-year running back Carlos Hyde doesn’t have the same reputation yet as Lynch and Charles, but he’s having a better statistical season thus far than those two.

Hyde entered Week 4 as the league’s third-ranked runner in total rushing yards. Plus, his 4.9 yards per carry average is tied with Adrian Peterson.

If Mike Daniels, B.J. Raji and company can leave San Francisco having kept Hyde from a big game, the Packers can start to feel pretty good about their run defense.

5. Translating Packers’ home dominance on the road

Lambeau Field has provided home-field dominance for Green Bay. It’s also where Rodgers has thrived at unbelievable levels. And while the Packers haven’t been bad on the road, this will be a good test to see if they can sustain their current level of play away from home.

Traveling two time zones west, and doing so on a short week, isn’t easy for an NFL team. Accordingly, McCarthy had the Packers leave a day earlier than usual in hopes of adjusting before kickoff. We wait to see if that strategy works.