Source: Manny Machado expected to have surgery on knee within a week. Likely lost for the season. Big hit for O's.— Tim Brown (@TBrownYahoo) August 22, 2014
Machado has been on the DL since Aug. 12 with a sprained right knee, so this would indeed constitute something close to a worse-case scenario.
The 22-year-old Machado is batting .278/.324/.431 (111 OPS+) in 82 games this season (and was strongly trending upward at the time of his injury). Besides a developing bat, he boasts elite defensive skills at third. His start to the 2014 season was delayed because of surgery to repair a ruptured ligament in his left knee in October of last year.
Needless to say, Machado will be missed by the first-place Orioles if he's indeed bound for season-ending surgery. The O's have been giving Chris Davis some time at third in Machado's absence, and Ryan Flaherty and possibly Cord Phelps can provide depth. Any of those arrangements, however, is obviously a significant downgrade from Machado.
For what it's worth, the Orioles have managed to go 26-18 without Machado this season.