Last night, it was stated that Red Sox righthander Daisuke Matsuzaka was “leaning” toward having Tommy John surgery. Today, via tweet from SI.com’s Jon Heyman, we learn that it’s official:

Dice-k will have tommy john surgery. Dr. Lewis yocum will perform, probably next week.

Recovery from TJ surgery can take quite a long time, perhaps up to 18 months. The Nationals’ Stephen Strasburg, who had TJ surgery early last September, isn’t expected back until next season. Matsuzaka will miss the rest of this season and probably all of 2012.

Perhaps coincidentally, 2012 will be the last year of the six-year deal he signed with the Red Sox before the 2007 season, when he was “posted” by his NPB team in Japan, the Seibu Lions. The Red Sox paid Seibu a $51,111,111 “posting fee” and are paying Matsuzaka $52 million over the six years, which can only be described as “disappointing”; Dice-K has posted a 49-30 record, but with a pedestrian 4.25 ERA and 108 ERA+, which means he’s been worth only 8% over league average for the last four-plus seasons.