By BRIAN WACKER

Jason Day was back to work on Monday morning at TPC Sawgrass, where he said his ailing back feels much better as he prepares for this week’s Players Championship.

It was his first time swinging a club since withdrawing from last week’s Arnold Palmer Invitational after playing just six holes in the opening round at Bay Hill.

“I feel great,” said Day, who arrived on Sunday night before playing 18 holes on Monday. “My back feels a lot better.”

The 31-year-old aggravated his back on March 2 and said he had trouble walking and sitting the next day. Then an MRI last Monday revealed a tear in his L4-L5 discs. Day teed it up anyway at Bay Hill, where he didn’t play a practice round and sat out the Wednesday pro-am, before pulling out of the tournament proper.

A photo of Day walking around Disney World on Friday created a social-media firestorm, though as the Aussie noted there’s little correlation between walking and swinging a club at 120mph.

Day, who won the Players Championship in 2016, will be making just his fourth start of the year this week. He finished 13th at the Sentry Tournament of Champions, was T-5 at the Farmers Insurance Open and T-4 at the AT&T Pebble Beach Pro-Am and is looking for his first victory since the Wells Fargo Championship last May.