Freel was placed on the 15-day disabled list on April 20 after being struck in the head with an attempted pickoff throw. He insisted he felt fine, and was disappointed about the conditions surrounding a stress test he was forced to take before beginning his rehabilitation assignment.
He was also frustrated over a lack of playing time.
Obtained in a December trade with Cincinnati, Freel hit .133 in nine games with Baltimore.
Gathright was batting .214 with Chicago this season. He will be assigned to the Orioles' Triple-A team in Norfolk.