The phrase "a marginal player" is correct and usable in written English.
It can be used to describe someone or something that has a minor or insignificant role in a particular context, such as a market or competition.
Example: "In the competitive tech industry, many startups are considered a marginal player compared to the established giants."
Alternatives: "a minor participant" or "a peripheral player".
[C9.] Brasil Telecom Raises Its Profile Only a year ago, Brasil Telecom seemed to be a marginal player in its home country.
Only a year ago, Brasil Telecom seemed to be a marginal player in its home country, providing telephone service in southern and west-central Brazil.
The team will send a marginal player to the Angels in return.
Mr. Nystrom and Mr. Lyons were among the best at their positions, while Mr. Nitti called himself "a marginal player".
The federal government is usually only a marginal player in actual crime fighting, which is overwhelmingly a local function".
Congress has assumed a secondary role to the executive, and the Supreme Court is "a marginal player".
Back then the Dodgers had a peppy first-base coach named Jake Pitler, a onetime marginal player for Pittsburgh who took it on himself to remind the players to expunge games from their memory once they were over.
To do so would be an extraordinary development for the Sweden Democrats, a previously marginal player in Swedish politics, with roots in neo-Nazism and fascism, which has been ostracized by other parties since it first crossed the 4 percent threshold for parliamentary seats in 2010.
It gratified me that even if I was a very marginal player in his drama, nevertheless he accorded me all his warmth and cleverness and kindness, if only for an evening.
Comparing Mr Berezovsky to Owen Glendower in Shakespeare's Henry IV Part 1, he said: "Mr Berezovsky has found it very difficult to accept that, for all his former importance as a power broker and for all the great wealth that he has obtained by that means, in business terms he was a relatively marginal player.
Introducing more sources of strife into the region by allowing al Qaeda and its cohort to take over Mali, if that's what's at stake, is a direct blow to U.S. interests, even as Mali seems a distant and marginal player on the world stage.
