9 of the most difficult courses on the PGA Tour this season

PGA Tour players make the game look so easy that it's difficult for the average golfer to fathom that there are actually courses out there that give the world's best an extra hard time.

It isn't always a birdie-fest. While it's rare, there are still tournaments out there where "par" is a player's friend.

Here's a look at the nine most difficult courses on Tour so far this season.

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9. TPC San Antonio - AT&T Oaks, home of the Valero Texas Open.

The 7,435-yard, par-72 played to a scoring average of 72.853 -- nearly an entire stroke over par. The winner, Kevin Chappell, finished at 12 under. He and runner-up Brooks Koepka at 11 under, where the only players in the field to reach double digits under par for the week. In total, 33 players finished the week under par.

Here are the scores the course yielded:

Eagles: 24
Birdies: 1,460
Pars: 5,182
Bogeys: 1,441
Double bogeys: 176
Other: 33

8. Bay Hill Club & Lodge, home of the Arnold Palmer Invitational.

The 7,419-yard, par-72 played to a scoring average of 72.890. Tournament winner Marc Leishman had a winning score of 11-under 277, a stroke better than Kevin Kisner and Charley Hoffman. The were the only three players in the field to turn in a 72-hole total with double digits under par. In all, there were 33 players who finished the tournament with an under-par score.

Here are the scores the course yielded:

Eagles: 37
Birdies: 1,220
Pars: 4,212
Bogeys: 1,228
Double bogeys: 145
Other: 34

7. Colonial Country Club, site of the DEAN & DELUCA Invitational.

One of the PGA Tour's truly classic venues, Colonial plays at 7,209 yards and a par of 70. During the tournament, the scoring average was 71.154. Kevin Kisner won the tournament and was the only player in the field to finish with a score that was double digits under par at 10-under 270. In all, 28 players finished 72 holes with an under-par score.

Here are the scores the course yielded:

Eagles: 5
Birdies: 1,134
Pars: 4,361
Bogeys: 1,224
Double bogeys: 152
Other: 18

6. Erin Hills, site of the U.S. Open.

While Erin Hills has played as the sixth most difficult course on Tour this season, it also played as the easiest of the four majors -- a surprising revelation given how brutal we're used to seeing most U.S. Open set ups. The 7,741-yard, par 72 -- the longest of the nine courses on this list -- played at more than a full stroke over par with a 73.204 scoring average. Brooks Koepka claimed his first major win and, in the process tied the U.S. Open scoring record. He finished the week at 16-under 272, which was four shots better than Brian Harman and Hideki Matsuyama. Twenty-eight players managed to finish the week under par.

Here are the scores the course yielded:

Eagles: 25
Birdies: 1,363
Pars: 4,953
Bogeys: 1,493
Double bogeys: 182
Other: 30

5. TPC Sawgrass, home of the Players Championship.

The par 72, 7,189-yard course had a scoring average of 73.291. Si Woo Kim, a winner by three strokes over Louis Oosthuizen and Ian Poulter at 10-under 278, was the only player to reach a score that was double digits under par. Only 21 players finished all 72 holes with an under-par score.

Here are the scores the course yielded:

Eagles: 38
Birdies: 1,429
Pars: 4,750
Bogeys: 1,410
Double bogeys: 238
Other: 55

4. TPC Potomac at Avenel Farm, host course for the Quicken Loans National.

The course -- a 7,107-yard, par 70 -- had a scoring average of 71.458. Tournament winner Kyle Stanley defeated Charles Howell III in a playoff. Both players finished 72 holes at 7-under 273, two strokes better than Rickie Fowler and Martin Laird. Twenty-five players finished the week under par.

Here are the scores the course yielded:

Eagles: 26
Birdies: 1,131
Pars: 4,255
Bogeys: 1,239
Double bogeys: 184
Other: 41

3. Royal Birkdale, site of the 2017 Open Championship.

The 7,156-yard, par 70 course had a scoring average of 71.852. Champion Jordan Spieth finished at 12-under 268, three strokes better than runner up Matt Kuchar and -- remarkably -- six strokes better than third-place finisher Hao-Tong Li. Twenty-one players completed 72 holes with an under-par total.

Here are the scores the course yielded:

Eagles: 36
Birdies: 1,169
Pars: 5,350
Bogeys: 1,605
Double bogeys: 191
Other: 37

2. Augusta National Golf Club, home of the Masters Tournament.

The scoring average on the 7,435-yard, par-72 course was 73.887. Winner Sergio Garcia and playoff runner-up Justin Rose each finished 72 holes at 9-under 279, three shots better than Charl Schwartzel. There were 15 players who finished the week under par.

Here are the scores the course yielded:

Eagles: 23
Birdies: 843
Pars: 3,113
Bogeys: 1,141
Double bogeys: 114
Other: 22

1. Quail Hollow Club, site of the 2017 PGA Championship.

The 7,600-yard, par-71 had a scoring average nearly 2 1/2 strokes over par -- far and away the most difficult this season -- of 73.468. Champion Justin Thomas at 8-under 276, was two shots better than Francesco Molinari, Louis Oosthuizen and Patrick Reed. Only 12 players finished the week with an under-par total. One other interesting note here too -- Quail Hollow allowed more eagles, 40, than any course on the list. It also produced 285 more bogeys -- 1,890 total -- than the next-closest tournament on the list in that category, the Open Championship.

Here are the scores the course yielded:

Eagles: 40
Birdies: 1,241
Pars: 4,822
Bogeys: 1,890
Double bogeys: 245
Other: 24