What's key for Tiger to notch No. 15?

There were 44 golfers under par after 18 holes. That number dwindled to just 10 after Friday's play ended at Kiawah Island's Ocean Course in the 94th playing of the PGA Championship.

With several notable names on the leaderboard, can Tiger Woods nab that elusive first major in more than four years? And if not Tiger, then who?

Our experts analyze all that and more in our latest edition of PGA Championship Four-Ball.

1. What does Tiger have to do if he wants to capture his 15th major championship this weekend?

Michael Collins, ESPN.com senior golf analyst: He's got to start finding a way to hit greens. With 36 possible in two rounds, he's hit 19. That's putting way too much pressure on the putter. Which, by the way, is finally acting like old times. But it can't forever, right?

Farrell Evans, ESPN.com senior golf writer: For starters, Tiger has to not play himself out of the tournament with a bad third round. With the difficulty of the Ocean Course, shooting even par on Saturday will set him up fine for Sunday. Then from there, it's just a survival of the fittest, and we know the 14-time major champion has been the last man standing many times in his career.

Bob Harig, ESPN.com senior golf writer: Hit more greens. He did well to hit nine during blustery conditions Friday, but has hit just 19 of 36 to this point. He can't expect to keep putting at the pace he has through two rounds.

Gene Wojciechowski, ESPN.com senior national columnist: Hope for the wind to blow again (he's a shot-maker in these kind of conditions) and keep making those vintage Tiger putts. Woods has been in position to win majors at the U.S. Open and the Open Championship. Can he do the coffee-for-closers thing this time?

2. How far back is too far back after 36 holes?

Michael Collins: Well, with the forecast saying the winds will be lighter at around 10-15 mph on Saturday, the golfers will have a chance to make a move. I'd say the guys at 2 over have a chance, but it'll take two great rounds to become the champion.

Farrell Evans: The large group at 2 over that includes Bo Van Pelt, Geoff Ogilvy and Padraig Harrington is in good position to get back into the tournament with under-par rounds Saturday.

Bob Harig: The conditions make this very interesting. They are such that a good round can move you up a bunch of spots. Players such as Ernie Els, Charl Schwartzel and Steve Stricker, who are 7 strokes back, should not be counted out. It is hard to envision anyone breaking away who is near the top.

Gene Wojciechowski: Depends on the weather. Trailing by 10 going into the weekend doesn't seem insurmountable -- if the weather kicks up and really rewards a low round. There were only five subpar rounds Friday.

3. Which player not named Tiger Woods has the best chance to win now come Sunday?

Michael Collins: Vijay Singh might have gone back to the person who helped him win the Masters by telling himself he's the best putter in the world. Maybe this week he's telling himself he's 39 again instead of 49. Whatever he's doing, it's working!

Farrell Evans: It's wide open, but I like Rory McIlroy to surprise us on the weekend. It seems like forever since he played well in any tournament, but at 2 under he's in a great position to get his second major.

Bob Harig: Rory McIlroy got away with a 75 on Friday and finds himself just 2 strokes back of the leaders. To shoot that high and really not lose any ground has to be encouraging.

Gene Wojciechowski: I'll go with Adam Scott. He's sort of lurking around, but he likes playing in tough conditions and his game can hold up in a major (yes, I remember the Open Championship).

4. Which American Ryder Cup hopeful do you think most needs a solid weekend?

Michael Collins: If Scott Piercy can find a way to have a big weekend and finish inside the top five, he might have played his way into a captain's pick. If not Piercy, then Bo Van Pelt could come back on the radar with a very strong weekend.

Farrell Evans:
Bo Van Pelt. The 37-year-old, top-10 machine is definitely on Davis Love III's radar, but he needs a big weekend to earn a place at Medinah. At 15th in the standings and never having been on a Ryder Cup or Presidents Cup team, Van Pelt probably isn't the first player you would pick if you were Love.

Bob Harig: Bo Van Pelt. He needs to make the team on his own, most likely, and is one of the few in position to do so from outside of the top eight automatic qualifier spots. He is tied for 24th in the PGA and can make a move with a solid weekend.

Gene Wojciechowski: Well, Rickie Fowler, Hunter Mahan and Brandt Snedeker missed the cut. Dustin Johnson, who did make the cut on the number, could really help himself with a strong showing.