Athletics prospects Leo De Vries, Jamie Arnold injured, out

Two of the Athletics ' top prospects, infielder Leo De Vries and pitcher Jamie Arnold, are out indefinitely with injuries.

De Vries, baseball's No. 2 prospect according to MLB.com, will undergo surgery on his right shoulder on Monday in Arlington, Texas. The 19-year-old, who was acquired last season when the A's traded closer Mason Miller to San Diego, was hitting .290 with 13 home runs, 55 RBI and 34 stolen bases at Double-A Midland, Texas.

Arnold, drafted 11th overall last year out of Florida State, took a line drive to his face Tuesday night while pitching for Triple-A Las Vegas. He has fractures to his intra-orbital and maxillary sinus. Arnold was promoted Sept. 1 and is 1-1 with a 1.80 ERA.

"Considering he took a ball to the face at 107mph, he's doing well," Arnold's mother, Dawn, posted on social media. "Has a few broken bones on his left side cheek and a corneal abrasion, but could've been so much worse."