Phil Mickelson won't be at the 2015 WGC-Match Play this week.
Mickelson, the 18th-ranked player in the world, has informed the PGA Tour he will not be in the field at the 64-man Match Play, according to the Golf Channel.
The only explanation Mickelson provided was "personal reasons." He will be replaced by No. 68 Mikko Ilonen.
"The Match Play format is the greatest format we could have for a golf tournament," Mickelson said earlier in the year. "I was not fond of the previous Match Play format because you didn’t know how long you were going to be around, and you didn’t feel like the best player was always going to be there on the weekend. This is a great way to get the best players to the weekend, keep it a pure match play form and keep it entertaining for the spectators. Now it can travel. Players won’t be shy because you know you will be playing three rounds. This is a great thing for the tournament."
On the tournament's website, Mickelson said, "I'm really happy with the new format and TPC Harding Park is a terrific setting for match play, so it's unfortunate that I won't be able to play this year."
Mickelson has a 16-11 record in his WGC-Match Play career and hasn't played in the event since 2011. He has not played since finishing second at the Masters in early April.