Duquette said there is inflammation in the elbow but no ligament damage. There are no plans for Harvey to undergo surgery.
MLB.com ranked Harvey, 19, as the Orioles' second best pitching prospect, behind Dylan Bundy, who is still recovering from Tommy John surgery.
Harvey posted a 3.18 ERA and 7-5 record over 17 starts in the Single-A South Atlantic League this season.
Baltimore selected Harvey at No. 22 in last year's draft. He was ranked the 58th-best prospect in baseball by Baseball Prospectus before this season.
The Orioles, who are said to have engaged in trade talks with Boston for ace Jon Lester, have reportedly refused to make Harvey or Bundy available in trade discussions.
A report Wednesday said Baltimore appeared "out of the mix" for Lester
- Chris Johnson