We present a monitoring study of SN 2004A and probable discovery of a progenitor star in pre-explosion HST images .
The photometric and spectroscopic monitoring of SN 2004A show that it was a normal Type II-P which was discovered in NGC 6207 about two weeks after explosion .
We compare SN 2004A to the similar Type II-P SN 1999em and estimate an explosion epoch of 2004 January 6 .
We also calculate three new distances to NGC 6207 of 21.0 \pm 4.3 , 21.4 \pm 3.5 and 25.1 \pm 1.7 Mpc .
The former was calculated using the Standard Candle Method ( SCM ) for SNe II-P , and the latter two from the Brightest Supergiants Method ( BSM ) .
We combine these three distances with existing kinematic distances , to derive a mean value of 20.3 \pm 3.4 Mpc .
Using this distance we estimate that the ejected nickel mass in the explosion is 0.046 ^ { +0.031 } _ { -0.017 } M _ { \odot } .
The progenitor of SN 2004A is identified in pre-explosion WFPC2 F814W images with a magnitude of m _ { F 814 W } = 24.3 \pm 0.3 , but is below the detection limit of the F606W images .
We show that this was likely a red supergiant ( RSG ) with a mass of 9 ^ { +3 } _ { -2 } M _ { \odot } .
The object is detected at 4.7 \sigma above the background noise .
Even if this detection is spurious , the 5 \sigma upper limit would give a robust upper mass limit of 12 M _ { \odot } for a RSG progenitor .
These initial masses are very similar to those of two previously identified RSG progenitors of the Type II-P SNe 2004gd ( 8 ^ { +4 } _ { -2 } M _ { \odot } ) and 2005cs ( 9 ^ { +3 } _ { -2 } M _ { \odot } ) .