Brooks Koepka reflects on the final day of the PGA Championship and explains what it means to have won so many majors at just 29 years old. (2:59)

FARMINGDALE, N.Y. -- Leading into the PGA Championship, one player was the topic of conversation. That would be Tiger Woods. Once play began, one player was the topic of conversation: Brooks Koepka.

So, after watching Koepka defend his PGA Championship for his fourth major in his past eight tries, it's fair to ask: What's his ceiling? And what to expect from Tiger going forward -- more like what we saw at the Masters, or more like what we saw at the PGA?

Our experts both look back on the PGA and into the future:

1. Brooks Koepka threw it out there at the beginning of this week that 'double digits' was in play for him for career majors. So, how many majors does he win?

Bob Harig: Seven. He is making it look easy right now, but we all know that it is not. Rory McIlroy seemed destined for double-digit majors five years ago and is stuck on four. Jordan Spieth, same thing. It's hard to win them, and while he's got a great formula, stuff happens. And let's say he does get seven. That is still phenomenal.

Michael Collins: Twelve ... if he stays healthy. I think his philosophy on how to approach tournaments is working pretty damn well so far. Why would he change anything? Let's say he has 10 more "solid" years -- that's 40 major chances. What has he shown that would make you believe he can't go 8-for-40?

Ian O'Connor: I love the fact that Koepka is gunning for 10 or more and, according to his former college coach, gunning for Tiger's 15 and Jack's 18. But since his great uncle Dick Groat was buddies with another slugger with blacksmith arms, Arnold Palmer, I'll give Brooks Arnie's seven.

Mark Schlabach: If Koepka stays healthy, I think he'll have a chance to reach double digits, but that's a tall order for anyone. Let's not forget that there are only three men in history -- Jack Nicklaus (18), Tiger Woods (15) and Walter Hagen (11) -- who have reached double digits. While Koepka knows he's the guy to beat every time he shows up to a major and isn't afraid to say it out loud, he has shown some nerves on Sunday in back-to-back majors at the Masters and PGA Championship. It cost him a green jacket and nearly cost him a second Wanamaker Trophy on Sunday.

Kevin Van Valkenburg: Ten majors is such an insane climb, it feels ridiculous to suggest he'll get there. I'm going to say there is no way he gets there, just so that someone can quote this out of context, selectively editing it and letting it serve as motivation for the next 20 years. Have you stopped reading, Brooks? Good. Because I'm actually bullish on his chances. Yeah, it's hard to sustain this kind of play, but there aren't any flaws in his game. His swing is so in balance. He might win 10 majors just by winning U.S. Opens and PGAs.

Nick Pietruszkiewicz: So, we should approach this one cautiously. And Bob's argument is the perfect one. A player has one or two great, great years and we think he's headed for history, forgetting the most basic rule: Golf is hard. Granted, Koepka has power and can dismantle courses -- more than Rory and way more than Spieth -- but an additional two or three feels more reasonable than (at least) six more.

2. Who (or what) will be Koepka's biggest hurdle this year? Next year? Next five years?

Harig: Golf. The ultimate game of frustration. It could be that a venue doesn't suit him; or that somebody gets hot; or that he even blows a big chance. Nobody made an issue of it, but Koepka had a great chance to win the Masters. Hit a ball in the water on 12. Missed two very makeable putts on 17 and 18. He could not pull that one off, and it's hard to knock him for it.

Collins: Time management. The more you win, the more people want your time, the less time you have to be the player you are/were. He will keep the chip on his shoulder for plenty of time to come, but in about four years with a couple of more majors under his belt, there will be a new, younger generation of tour pros who can do what he's doing now, and they will be the second-biggest hurdle for him.

O'Connor: Trying to improve his performances in the non-majors to enhance his historical standing in the game. It's going to be weird five years from now if Brooks has seven majors and only, say, 12 or 13 total victories. At some point, the guy dominating the majors needs to figure out how to win some minors.

Schlabach: Is it his ego? Can he become too overconfident? He seems like a guy who's going to do everything imaginable to keep his body and game in shape at the highest levels, but how long can it last? How long can he maintain his laser focus at majors? We saw Rory McIlroy, Jordan Spieth and others slip after similar streaks. Is Koepka really that much different?

Van Valkenburg: Juggling family life and wear and tear on his body. Life comes at you fast when you get married and start a family. If Koepka wants either of those things, it will eventually create an emotional tug-of-war between that stuff and golf. There just aren't enough hours in the day to practice as much as you want, get your workouts in to maintain your body and be a present father and husband. Everyone thinks they can fit it all in, and everyone struggles. What if he chooses family life and practice and has to neglect some workouts? Does his body start to break down? Does his game slip because he can't practice as much? How he handles those complexities probably determines how high his ceiling is.

Pietruszkiewicz: It's hard to pick one or two. There's injury and life and expectations and pressure. There's also, you know, Rory and DJ and Tiger and Rose and ... you get the point. Majors have big fields, with plenty of talented players and more on the way.

3. What do you make of Tiger's week? Cause for concern? No big deal?

Harig: It's somewhere in between. Tiger earned himself the benefit of the doubt with the Masters win. Bouncing back from that and getting re-energized again was never going to be easy. But what the PGA did show was that he will have to put in more preparation to win these big tournaments, and he won't be able to do it with a lackluster game. Woods built his way toward the Masters; he'll need to do the same thing heading into Pebble Beach.

Collins: No big deal. This is the bed the PGA Tour and PGA of America made when they changed the schedule. Sleep well ... 'cause Tiger will never contend in a PGA Championship coming off a week in which he plays great at the Masters. The new Tiger body-recovery schedule doesn't match the "let's have a major every four weeks" schedule.

O'Connor: Not a big deal. Deep down, he knew he had almost no chance at Bethpage. He had no post-Masters reps, got sick Wednesday, and got paired with a fire-breathing dragon in Koepka. If Tiger misses the cut at the Memorial and then doesn't contend at Pebble Beach, then it will be time for Tiger fans to worry a bit.

Schlabach: I'm not sure if we could have expected much more after he failed to play competitively after winning the Masters. Not even Tiger can do that at age 43. He didn't even play a full practice round and came down with an illness before the first round at Bethpage. I think he'll have to play at the Memorial in preparation for the U.S. Open, and he's going to have to work his way in shape physically and mentally like he did before Augusta.

Van Valkenburg: Not a concern. To be frank, I don't think he's going to be able to compete on courses like this in his 40s. They require too much raw power, and his strength, especially over four days, is going to be his artistry. I actually think the "rust" stuff is overrated. Even if he was healthy and rested, I don't think he'd have been in the mix here. But Pebble and Royal Portrush require a lot more shot shaping and thinking, and I think he'll be a factor in both if he can get loose and the weather cooperates.

Pietruszkiewicz: No big deal at all. The combination of it all -- the emotional Masters, the lack of preparation before he got here and then when he got here, the length of Bethpage Black -- was too much. It was predictable before it started. Actually, it might have been the only thing I said before this event that I got right. Expect him to be in the mix when we get to Pebble Beach in a month for the U.S. Open. This was a blip, a passing thunderstorm that'll move out in a day or two.

4. Higher hopes for the U.S. Open: Tiger or Phil?

Harig: Tiger. Strategic courses are going to be Tiger's best bet going forward. Places where you have to play chess throughout the tournament. Placing shots in the correct spots. Hitting irons or fairway woods off tees. That helped Tiger at Augusta and will at Pebble Beach. Phil can certainly play that game, but even he admits he cannot just bomb drivers like he did when he won the tour event in February. It's a different course for the U.S. Open. You have to be more defensive. That is more suited to Tiger.

Collins: The last time it came down to Tiger and Phil at Pebble Beach, Phil kicked Tiger's behind ... but this is the U.S. Open, so it'll be an entirely different beast. Still, Tiger got his comeback win of the ages at the Masters. It would be cool to see Phil finally complete the career grand slam at Pebble Beach. That would give Pebble the two greatest U.S. Open's ever -- and we lived through them both!

O'Connor: I'd still say Tiger. He had his most dominant performance at Pebble, and though that was nearly two decades ago, that has to count for something. If he gets locked in at the Memorial, I'll feel better about this call. If he doesn't play at Jack's place or misses the cut, I won't.

Schlabach: Tiger. Even though Phil won at Pebble Beach earlier this year and has a mighty good track record there, his game hasn't been very good since his last win. He's missing too many fairways and, frankly, his putting has been pretty subpar, as well. There's going to be so much pressure on Phil to complete the career grand slam after so many near-misses at the U.S. Open. At age 48, he knows his window is closing rapidly. How much does he press?

Van Valkenburg: Tiger. Phil is more likely to miss the cut at Pebble than he is to pull off a miracle win. The reason Phil was so dejected at Merion in 2013 is he knew -- deep down -- that was his last real chance. For all the talk of how far he's hitting it in his 40s, he's 94th on Tour this year in strokes gained off the tee. He's 127th in strokes gained putting. We think of Tiger as being a little wild off the tee at times, but Phil is one of the least accurate players on Tour this year, hitting barely 50 percent of his fairways (212th on Tour). As much as I'd love to see it, he's not winning at Pebble.

Pietruszkiewicz: I'm going to say it's the same, because both can (and will) play well at Pebble. It's a way smaller ballpark than Bethpage Black. They know the place so well, each having won on it more than once. (Granted, one of those for Tiger was a major.) Would it surprise me if both were in the top 10 at Pebble? No, not at all. Just like it wouldn't surprise me if Tiger won. I don't see Phil winning -- though, wow, that would be some story: He completes the career grand slam by finally winning a U.S. Open, on his birthday, on Father's Day, 20 years after his emotional moment with Payne Stewart at Pinehurst.

5. Who had the most disappointing week?

Harig: Rory McIlroy. Give Rory credit for grinding to make the cut on Friday when he appeared way out of it. But Rory isn't about making cuts, and Bethpage seemed perfect for him: long course, soft due to rain. That's been the setup for each of his four major championship victories. And yet McIlroy, despite playing well this year, seems to get in his own way at the majors. It is a frustrating period for him.

Collins: Tony Finau. Straight and long with a great attitude. The PGA Championship at Bethpage Black was set up perfectly for another first-time major winner to take his place among the elite. Instead, Finau ended up being ranked 38th in strokes gained off the tee and 79th in strokes gained putting. Saturday's 1-under 69 was the only round he could manage under par. Coming off the fifth-place finish at the Masters there were high hopes for Finau. Bethpage Black crushed those.

O'Connor: Rory McIlroy. When he won The Players in March, I figured this might be the year Rory becomes Rory again in the majors. But he was a nonfactor at Augusta, and a nonfactor here, and now I'm thinking he'll be a nonfactor at Pebble, too. Will golf's Lost Boy finally make it home at the Open in Northern Ireland?

Schlabach: I'm not going to pile on McIlroy, so I'll go with Bubba Watson. He has been one of the longest hitters on the Tour this season, but he didn't even make the cut at Bethpage. He has two green jackets, but Augusta seems like the only place he plays well in majors anymore. He has missed the cut in five of the past seven majors.

Van Valkenburg: Here is a fun exercise: When is the last time Bryson DeChambeau was in contention at a major on the weekend? It's the 2016 U.S. Open, when he was an amateur. I love DeChambeau's personality, even if the science behind his methods often doesn't hold up to even the slightest scrutiny. But it's time to start contending in majors if he wants to be in the game's top tier. You can say, "He's only 25!" but by that age, Jordan Spieth and Rory McIlroy had each won three majors. (DeChambeau has never finished in the top 10 at a major.) Missing the cut here and grumbling about the setup wasn't the best look.

Pietruszkiewicz: Tommy Fleetwood. We keep saying one of these days Fleetwood is going to win a major. Well, he opened with 67 and was within shouting distance of Koepka. Then he went 71-72-78. And this was after he was a nonfactor at the Masters, where he finished 36th. Maybe things will get better at Pebble Beach.