This article says Landon Schaefer announced he's attending Arkansas but doesn't provide a source or link to the news.
4 Signing Class Remains Mostly Intact
Despite owning the No. 4 signing class in the country, Arkansas had only two high school signees selected in the MLB Draft — and one of them has already announced he’s coming to school. Even if McLane Moody signs with the Pirates and skips college, the Razorbacks will still have plenty of young talent to work with next year.
Not only is Landon Schaefer (No. 71 on Perfect Game) making it to campus, but so are Jordan Martin (No. 75), Carson Brumbaugh (No. 77), Peyton Lee (No. 166), Alexander Peck (No. 175), Joey Lorenzini (No. 218), Tye Briscoe (No. 256), Luke Cornelison (No. 262) and Mark Brissey (No. 265).