Pandas: duplicate row by splitting the value of one column

Question

I have:

df = pd.DataFrame({'Name':['Chris Iannetta', 'John Hicks'], 'Pos':['C', 'C/1B'], 'HR':[12, 4]})

I want:

df_new = pd.DataFrame({'Name':['Chris Iannetta', 'John Hicks', 'John Hicks'], 'Pos':['C', 'C', '1B'], 'HR':[12, 4, 4]})

Thanks!