I agree that it needs more food. However, there is not currently a way to get more food. We have growth in 6 turns, and we have a cottage up already, so building more cottages is not a priority. If the worker is going to be useful elsewhere for now, by all means, let's do that. I would reccomend mining the grassland hill on the river to give us a way to squeeze out a few more hammers at the cost of stagnating our growth.
If you're worried about farms being placed on those grassland tiles in the future, perhaps we should mine the grassland hill on the river and work that, stagnating our growth for now? More population isn't always a good thing if it's not useful, as it does drive up maintenance.
Also, the worker can still chop the forest on at least the plains hill and the southern grass hill to give us a production boost. We will likely be mining these eventually anyway, and the forest gives us no real benefit there.