Zaun was claimed off waivers by the Tampa Bay Rays GM Andrew Friedman in exchange for Rhyne Hughes on August 7, 2009. On August 16, Zaun hit a pinch hit grand slam home run against his old team the Blue Jays in the 8th inning off Brandon League on a 3–2 fastball. On November 12, 2009, Zaun was granted Free Agency. On December 4, 2009, Zaun signed a one-year contract with the Milwaukee Brewers for $ million. After suffering a severe injury, Zaun's 2010 season—and, as it turned out, his MLB career, ended on May 20. After the season, Milwaukee declined his contract option, and he became a free agent on November 2.
Testosterone can be administered parenterally , but it has more irregular prolonged absorption time and greater activity in muscle in enanthate , undecanoate , or cypionate ester form. These derivatives are hydrolyzed to release free testosterone at the site of injection; absorption rate (and thus injection schedule) varies among different esters, but medical injections are normally done anywhere between semi-weekly to once every 12 weeks. A more frequent schedule may be desirable in order to maintain a more constant level of hormone in the system.  Injectable steroids are typically administered into the muscle, not into the vein, to avoid sudden changes in the amount of the drug in the bloodstream. In addition, because estered testosterone is dissolved in oil, intravenous injection has the potential to cause a dangerous embolism (clot) in the bloodstream.