The early years of the National League were tumultuous, with threats from rival leagues and a rebellion by players against the hated "reserve clause", which restricted the free movement of players between clubs. Competitive leagues formed regularly, and also disbanded regularly. The most successful was the American Association (1881–1891), sometimes called the "beer and whiskey league" for its tolerance of the sale of alcoholic beverages to spectators. For several years, the National League and American Association champions met in a postseason championship series—the first attempt at a World Series .
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.