the Memorial Tournament presented by Nationwide Insurance: Moved into a tie with Jack Nicklaus for second on the all-time PGA TOUR victories list, with 73, after his two-shot victory at the Memorial Tournament. Trails only Sam Snead's 82 wins after a two-shot victory over Andres Romero and Rory Sabbatini at Muirfield Village GC. Posted his 73rd career victory at age 36 years, 5 months, 4 days, nearly 10 years younger than Nicklaus when he won his 73rd tournament (46 years, 2 months, 23 days) and almost seven years younger than Snead when he posted his 73rd victory (43 years, 9 days). Collected his fifth career victory at the Memorial Tournament and won in come-from-behind fashion for the 21st time in his career after entering the final round four shots off the 54-hole pace. Trailed Sabbatini by two shots standing on the 15th tee but played his final four holes in 3-under, making birdie on Nos. 15, 16 and 18. Holed a flop shot from 49 feet, 10 inches from behind the green at the par-3 16th to tie Sabbatini for the lead at 8-under. Won the Arnold Palmer Invitational and the Memorial Tournament in the same year for the fourth time (2000-01, 2009 and 2012). Posted the 12th victory of his career in Ohio and won multiple tournaments in a season for the 13th time in his career.
A related effect was measured by University of California economist Jennifer Brown, who found that other golfers scored higher when competing against Woods than when he was not in the tournament. The scores of highly skilled golfers are nearly one stroke better when playing against Woods. This effect was larger when he was on winning streaks and disappeared during his well-publicized slump in 2003–04. Brown explains the results by noting that competitors of similar skill can hope to win by increasing their level of effort, but that, when facing a "superstar" competitor, extra exertion does not significantly raise one's level of winning while increasing risk of injury or exhaustion, leading to reduced effort.
Surgery: Pulled out of next two PGA TOUR starts, the Genesis Open and The Honda Classic. Released statement: "My doctors have advised me not to play the next two weeks, to continue my treatment and to let my back calm down. This is not what I was hoping for or expecting. I am extremely disappointed to miss the Genesis Open, a tournament that benefits my foundation, and The Honda Classic, my hometown event. I would like to thank Genesis for their support, and I know we will have an outstanding week." In April, announced on his website he had undergone further back surgery. The operation was performed by Dr. Richard Guyer of the Center for Disc Replacement at the Texas Back Institute.