Matheny, the son of Cardinals manager Mike Matheny, just finished his junior season as an outfielder at Missouri State, where he hit .291 with a .417 on-base percentage, 18 doubles, five home runs, 43 RBIs and 12 stolen bases. Matheny, ranked the Draft's No. 103 prospect by MLB.com, had not signed after St. Louis selected him in the 23rd round out of high school in 2012.
Boston also reached agreements with outfielder Jagger Rusconi (fifth round), left-handed pitcher Logan Allen (eighth round) and right-hander Nick Duron (31st round). Rusconi, out of West Ranch (Calif.) High School, is a switch-hitter whom the Red Sox expect to start in center field. Allen, a 6-foot-3 southpaw from the IMG Academy in Florida, was signed away from a commitment to the University of South Carolina.
The Sox now have deals with 14 of their 39 picks, though first-rounder Andrew Benintendi, a University of Arkansas center fielder, is not among those.
Andrew Simon is a reporter for MLB.com. Follow him on Twitter @AndrewSimonMLB. This story was not subject to the approval of Major League Baseball or its clubs.