The Brazilian came out of his short-lived retirement at the start of the year to allow former team-mate Valtteri Bottas to join Mercedes and has enjoyed some steady if unspectacular results.
Perhaps more importantly, he has helped mentor rookie Lance Stroll, but with the Canadian's position for next year guaranteed, there is less certainty over who will partner him.
Both Robert Kubica and Paul di Resta have been testing with the Grove outfit in recent days and will have other chances to prove themselves in the next few weeks.
Paddy Lowe has insisted Massa remains an option but there is a suggestion Williams could struggle to match the 36-year-old's current wages.
The man himself believes he and Stroll have struck up a strong partnership and feels the team would be making a mistake by choosing to break their bond.
"I think it's frustrating that the team is trying to go for a direction that can really be much worse for the team than keeping the same [drivers]," said Massa.
"Lance is growing a lot and to be honest I'm really doing a great job with my driving, so I think the team has a direction that it can just be positive to keep it the way it is. If the team changes something, they can pay more than it costs to keep me!
"I think the team knows 100 per cent what I am able to do. Where I am in the classification in the championship now I am not because of my mistakes, I am because of things that happened in three races, that I lost maybe 30 points.
"If I had the points that I'm supposed to have, not from my mistakes during the season, I would have been maybe fighting very close to the Force India guys."