I dug deeper to see which became full time starters after relieving for an extended period of time. We have Kim, Rawley, Allen, Daal, and maybe Hernandez. Hernandez was brought up as starter. Moved to pen for 3 years until 1980 where he started 7 games and pitched 108.1 innings. The next year in 1981 he pitched in 12 games. Why did he only pitch in 12 games? Did the Cubs try and convert him to a starter that year only for him to get hurt and come back late in the year and relieve? He stayed in the bullpen after that.

You mentioned Kim's injuries.

Rawley performed miserably for New York in 1984 while only pitching in 29 games 1 1/2 years after making the transition to starter. Was he ever injured? He straightened himself out with Philly and became solid. Settled in and made an All Star team in 1986, but also missed starts. Only started 26 games that year, but after starting for that long I don't want to speculate that this was because of the conversion.

Allen started some in 1983 and didn't start again regularly until 1986, when you said he had those injuries. You also said he had them in 1985, but he didn't start any games that year, so it's most likely that those events are dependent of each other.

Dall spot started in minors. Became regular starter in 1998 and performed admirably. Hit a bump in 2000, 19 losses and a 6.14 ERA while making only 16 starts and pitching in 20 games. Did Dall suffer some sort of injury? He was never the same starter after that.

My results are just as inconclusive as yours but there is a pattern that suggests that you shouldn't move starting pitching prospects to the bullpen if you plan on them starting for you in the future.