Watson's six-paragraph statement released through the PGA of America came after four unnamed sources revealed details, for a story published by ESPN.com on Friday, of a team bonding session at the Gleneagles Hotel in Scotland last weekend that went bad.
"First, I take complete and full responsibility for my communication, and I regret that my words may have made the players feel that I didn't appreciate their commitment and dedication to winning the Ryder Cup,'' Watson said in the open letter. "My intentions throughout my term as captain were both to inspire and to be honest.
"Secondly, the guys gave everything. They played their hearts out. I was proud to get to know each and every one of them. I know they are all going to win tournaments, be on future Ryder Cup teams and have wonderful careers.''
Watson, 65, was the oldest captain in Ryder Cup history when the event was played last weekend at Gleneagles, where the U.S. suffered a 16 to 11 defeat, its eighth in the last 10 Ryder Cups.
Watson is the last captain to win a Ryder Cup on the road, doing so in 1993. He was brought back to try and regain a Cup that has been elusive to the American side, but his weekend was marked by second-guessing and what turned out to be some bruised feelings among American players -- especially from Phil Mickelson, who wasted no time in voicing his concerns about the entire Ryder Cup process following the closing ceremony Sunday.
Mickelson's blunt assessment turned out to be fueled, in part, by a Saturday night session in the U.S. team room that was attended by more than 40 people, including players, caddies, spouses, girlfriends, workers and PGA of America officials.
According to the sources, Mickelson was one of several players who took issue with the way Watson handled his remarks to the team, as well as his response to a well-intended session in which he was presented a gift by team members.
Mickelson, who earlier that day sat out an entire session for the first time in 10 Ryder Cup appearances, also felt the need to address the team to change the tone.
"As for Phil's comments, I completely understand his reaction in the moment,'' Watson said in the statement. "Earlier this week I had an open and candid conversation with him and it ended with a better understanding of each other's perspectives. Phil's heart and intentions for our team's success have always been in the right place. Phil is a great player, has great passion and I admire what he's done for golf.''
Watson is one of the game's greats, an eight-time major champion who won five Open Championships, including four in Scotland. At age 59, he nearly won a record-tying sixth Open, losing in a playoff to Stewart Cink at Turnberry in 2009.
He also won 39 times on the PGA Tour and played on four U.S. Ryder Cup teams.
The PGA of America, which chooses the U.S. captain, made him the first to repeat in that role since Jack Nicklaus in 1987, but his tenure was marked by a lack of communication and second-guessing of his pairings during the U.S. defeat.
"The bottom line is this: I was their captain,'' Watson said in the statement. "In hindsight whatever mistakes that were made were mine. And I take complete and full responsibility for them.
"I want to say again to the players, their families, the PGA and our country how proud and honored I was to captain this talented group of golfers, and how privileged I was to spend the past two years working this labor of my love for the Ryder Cup.''
Watson Takes Responsibility
ESPN Golf senior writer Bob Harig talks about Tom Watson's taking "complete and full responsibility" for any mistakes he made as captain of the U.S. Ryder Cup team.