Boston places RHP Buchholz on 15-day DL
To take his place, the club selected left-hander Brian Johnson, a highly touted prospect, from Triple-A Pawtucket Saturday before their game against the New York Yankees.
The 30-year old Buchholz walked off after throwing a cutter clocked at 84 mph to Stephen Drew in the fourth inning of Friday night's loss.
The 24-year-old Johnson is 8-6 with a 2.73 ERA with 81 strikeouts and 26 walks in 85 2/3 innings.
Buchholz was 4-0 with an 0.87 ERA in his last four starts before losing Friday.