4 players who rebounded Friday at the PGA Championship

The humdrum opening round at the PGA Championship yielded a relatively underwhelming leaderboard, the names at the top offering little in terms of star power.

But while some dispiriting performances - namely Dustin Johnson's - spilled into the second round, other enticing entries infiltrated the tournament's top rungs.

Here are four big names who bounced back Friday, in turn shoring up the leaderboard:

Jason Day

The defending champion's dazzling efficiency from tee to green was finally rewarded with some made putts in Round 2. Day knocked in eight birdies, including seven in an eight-hole stretch, and climbed to within two shots of the lead.

Jordan Spieth

Starting on the inward nine, Spieth made five birdies on his first nine holes, to move within a shot of Jimmy Walker's 18-hole lead, but failed to continue making inroads in the latter half of his round. Regardless, Spieth's 67 - his lowest round at a major since Thursday at the Masters - has spring-boarded him into contention.

Patrick Reed

Five birdies over his first 11 holes saw Reed jump out to a share of the lead early in the morning. He finished his remaining holes at even par, holding on to match the tournament's low round of 65. He's 9-under par over his last 30 holes.

Rickie Fowler

Fowler was stuck in the mud, unable to build on his encouraging start through 16 holes Friday - then he arrived at the long holes. Fowler used seven strokes on the final two holes - Baltusrol's only par 5s - and wound up at 4-under for the tournament with his birdie-eagle finish.