US captain Steve Stricker admitted he "lost sleep" over his decision not to give Patrick Reed a wild card for this month's Ryder Cup.

Reed has revelled in the nickname of "Captain America" since being the leading American points scorer on his 2014 debut and famously beat Rory McIlroy in a thrilling opening singles match at Hazeltine two years later.

However, the former Masters champion's serious recent health scare counted against him, with Stricker opting for Jordan Spieth, Xander Schauffele, Harris English, Tony Finau, Daniel Berger and Scottie Scheffler.

"We were looking at the six players to perform here at Whistling Straits and we feel these six fit Whistling Straits to a tee," Stricker said.

Open champion Collin Morikawa, Dustin Johnson, Bryson DeChambeau, Brooks Koepka, Justin Thomas and Patrick Cantlay were the six automatic qualifiers.

Reed missed the first two FedEx Cup play-off events and revealed during last week's Tour Championship that he had been "battling for my life" in Houston Methodist Hospital after being diagnosed with double pneumonia.

"That was a very, very difficult call. Kinda lost sleep over that one," Stricker said of Reed.

"He is a tremendous competitor, his record at the Ryder Cup is pretty darn good. But I think it was just the uncertainty of his health and really the lack of play that led to our decision down the stretch.

"It was a very hard conversation. He was my first call. I knew it was going to be hard but he took it like a true champion.

"I apologised to him many times and just wanted to make sure he knew it was a very difficult decision. He was very disappointed as you can imagine but he said all the right things and handled it very well."

Stricker said he and his vice-captains had discussed the possibility of having to replace Koepka after the four-time major winner withdrew from the Tour Championship with a wrist injury, but added: "We're not there yet. We'll deal with that if it were to happen."

The 54-year-old also said all 12 of his players are set to play a practice round at Whistling Straits, adding: "My message from day one has been to try to out-prepare the European team. It's been that way throughout my career.

"Let's get in as much practice as we can and maybe take a little of the stress of Ryder Cup week off our plates."