It's only a very slight pinkish-cast, but I reckon it's worth a try to restore it. I've read online about what to do and the consensus seems to be:
- don't let it happen (not helpful - too late)
- don't let it dry out (not helpful - too late)
- try bleach (not helpful - label says don't use bleach)
The shirt is 77% cotton, 33% polyester and has a 'do not bleach' symbol.
I have confidence in the power of MN to advise which product will work!