Buckle up. On Sunday at the Copperhead, anything can happen

PALM HARBOR, Fla. – The Copperhead Course at Innisbrook Resort is aptly named. One never really knows when it will rise up and strike.

For Dustin Johnson, the final hole of the closing Snake Pit on Saturday – No. 18, an uphill par 4 measuring 445 yards – provided a highlight for the day. Facing an uphill shot, into the wind, from behind a high lip in a fairway bunker tucked along the right side of the fairway, Johnson ripped a full, towering 9-iron that stopped 10 feet right of the flagstick, setting up a closing, right-to-left swinging birdie putt to cap a round of 4-under 67.

“The golf course plays tough, which I like,” Johnson said, “and it’s going to be a good day tomorrow.”

Two groups behind Johnson, Englishman Paul Casey, defending his title at this week’s Valspar Championship, found a fairway bunker guarding the right side of 18 as well. He wasn’t as fortunate as Johnson. His second finished some 35 yards short of the green and he failed to get up and down. Bogey, his first since the second hole. What had been a three-shot cushion midway through the back nine had shriveled to a shot, with Johnson hovering closest to him, no less.

Valspar did something playful this week, allowing caddies who normally wear their players' surnames to have nicknames on the back of caddie bibs. There are caddies sporting nameplates such as Leaping Cougar, Ox, #CurryPower and Roo. Casey, who shot 68 on Saturday, still has plenty of work ahead if he is to live up to the playful moniker carried on the back of caddie John McLaren’s bib this week: It reads, simply enough, The Champ.

“Why not?” reasoned Casey late Saturday. “How many times do you get a chance to do that?”

All the high drama in front of a packed house at Valspar on Saturday sets the stage for another potentially thrilling finish. Casey has been the lone player this week to advance to double-digits under par, even though that didn’t last so long on one of the PGA TOUR’s toughest, yet fairest, examinations.

Luke Donald, who has battled back issues much of the last two years and is playing on the weekend of a PGA TOUR event for the first time in a year, battled valiantly to a round of 70 and is hovering at 6 under, very much in the mix, three shots behind his fellow Englishman. A television reporter asked Donald to offer his thoughts on what the reporter called his “average day.” Donald, as polite a man as you’ll ever meet, took some issue with that phrasing.

“Average? You go try and play out there,” Donald said. “It's pretty tough out there. I thought it was pretty good.”

It was very good. The Copperhead can be a beast, and few truly conquer it. Over four days, you pick at this course in small bits. Louis Oosthuizen had a chance to go deep on Saturday, getting to 7 under on his round through 13 holes, but he bogeyed two of his last three to shoot 66. Jason Kokrak matched it, but it took four birdies and an ace (218-yard 15th hole) over his final 12 holes to get there.

That’s why, on Sunday at Valspar, pretty much anything can happen. One week after a wild finish at THE PLAYERS Championship, where so many players had a chance to step up before Rory McIlroy seized the day, a dozen players will begin the final round within five shots of Casey. And don’t count those just outside that bubble out just yet.

“We have seen people come from behind, shoot good rounds, I think even the year I won (in 2012) I think Sang-Moon Bae or one of those guys who were in the playoff shot 64 or something and was seven or eight behind and got in the playoff (it actually was Robert Garrigus)," Donald said. "If you get on a hot streak and can get off early and with the greens a little bit softer, a little bit more receptive and make a few putts, six, seven shots still has a chance.”

Casey views Sunday as a complete bonus. The way he sees it, he already has one Valspar trophy – a large dimpled golf ball on the end of a sweeping long gold paintbrush – and going up against the very best player in the world is exactly what he wants. Had Johnson, a 20-time PGA TOUR winner, not birdied the last hole on Saturday to get to 8 under, Casey would have played Sunday alongside Kokrak, who is seeking his first victory. Instead, he gets Johnson, who is making his first start at Copperhead since 2010.

Why, exactly, is Casey so glad that he’s drawn Johnson for the final 18 holes?

“He’s the best player in the world,” Casey said. “That’s why I do what I do. You look at the board, who’s the obvious one? Dustin. Who’s the favorite tomorrow? Probably Dustin."

“My mindset now is I’ve won this, and I have nothing to lose. I have one of those trophies – yeah, I want another one – but tomorrow is going to be highly entertaining to me.”

And everyone else who shows up. Ah, Sunday at the Copperhead, 19th edition. Who will be stricken, and who will be the one who strikes?