To objectively evaluate the function of the throwing shoulder after an injury, a preinjury performance profile should have been recorded and a simulated game based upon this profile be established for comparison. The performance profile must include a strength or power component (fastball velocity), an accuracy component (fastball-for-strike percentage), and an endurance component (the decrease in fastball velocity per inning). The simulated game requires a specific number of innings, a specific number of pitches per inning, a pitch selection ratio, a rest interval between innings, and a means to record the data. This information is not available in most circumstances. The authors have collected data from 98 starting pitchers in the National Baseball League from 1983 through 1985 to develop a profile for those pitchers lacking preinjury performance profiles. Since 1983, in 486 games, 145,886 consecutive pitches were logged using a custom data form and entered into an IBM- 360 computer. Based upon the summation of the performance profiles of these pitchers, a simulated game should be 61/3 + 1 l/3 innings with 15 + 2.4 pitches per inning. The interval between innings pitched should be a minimum of 9 minutes and one should expect a 2% or 1.5 mph decrease in the fastball velocity from the first through the sixth innings with a fastball-for-strike percentage of 64%. While this is a study of major league starting pitchers, the concept of a preinjury performance profile to define full rehabilitation is applicable from the Babe Ruth league through professional baseball. J Ortho Sports Phys Ther 1987;9(3):101-105.