Song Sung-mun, a late-blooming star who has been among the best players in Korean baseball the past two seasons, has signed with the San Diego Padres, a source privy to the situation said Monday. The 29-year-old infielder, formerly of the Kiwoom Heroes in the Korea Baseball Organization (KBO), is taking his talent to Major League Baseball (MLB) on a four-year deal worth $15 million, according to the source. The Associated Press also reported the financial details of Song's contract, but the Padres had not officially confirmed the deal as of this writing. Reports of Song's deal with the Padres first surfaced Friday. Song had been posted for all 30 MLB clubs in November, and his 30-day negotiating window was to close at 5 p.m. (U.S. Eastern time) on Sunday, or 7 a.m. Monday (Korean time). While the Padres had not made their announcement by the posting deadline, the source said Song had already put pen to paper and the club's confirmation was a mere formality. Song made his KBO debut with the Heroes in 2015 after being selected in the fifth round the previous year, but he only had his first b