Jordan Spieth

IRVING, Texas — Jordan Spieth wasn’t sure what par was at his hometown AT&T Byron Nelson and thinks it actually might have helped him through some frustrating early holes.

There’s a reason the Masters champion was uncertain — overnight rain turned one of the signature par 4s at the saturated TPC Four Seasons into a pitch-and-putt par 3 at 105 yards for the second round Friday.

Spieth and every other early finisher within three shots of clubhouse leader Jon Curran turned in a birdie 2, and Gary Woodland had a hole-in-one when it was still possible that the easy wedge over a pond would play as a par 4.

Tour officials later made the switch.

“I was able to fire at more pins, not really worry about anybody else,” said Spieth, who shot 64 — 5 under because par became 69 to put him at 6 under for the tournament. “Really actually helped because I didn’t know what score I was at when it’s a par 4, 4 par, par 3, don’t really know what it’s at.”

Curran shot 63 and was at 9-under 130 with the two-round par total at 139 instead of 140, with several contenders unlikely to finish the round because of a three-hour delay at the start. Cameron Percy was a shot back after an eagle at the par-5 seventh for a 64.

The fairway at the normally 406-yard 14th was deemed unplayable in the landing area after 5 inches of rain fell starting about midnight, pushing the total to about 17 inches in less than three weeks at the Four Seasons course. Texas officials have declared May the wettest month in the state’s history.

Muddy footprints marked the area where a dip in the fairway funneled down to a rain-swollen canal off to the right.

Standing water covered the ground under some trees, about the same spot where Spieth chipped out in Thursday’s first round and ended up with a bogey.

Tour officials believe it was the first such alteration since the 2005 WGC-Match Play Championship, when flooding at La Costa in Carlsbad, California, temporarily turned a 467-yard par 4 into a 162-yard par 3.