Or, for all we know, maybe Brewer's being held back as some sort of secret weapon.
For now, Brooks seems content with his current bench production, continuing to trust the unit through thick and thin. It might not be the best strategy, but there are reasons Brooks hasn't gone to Brewer. Here are the five most likely.
A numbers game: it's the only real reason Brooks gives when asked why Brewer is not playing. But it's coach speak at best. For a team that prides itself as a defensive-minded club, the Thunder is playing Derek Fisher and, at times, Hasheem Thabeet ahead of Brewer. Yes, adding Brewer technically would bump the rotation to an improbable and possibly impossible 11 players. But nothing is stopping Brooks from altering his rotation and staying at nine and sometimes 10.
Familiarity: Fisher played here last year. Brewer didn't. Maybe that holds weight with the Thunder. Maybe not. But it certainly is a luxury. Fisher has been able to step in and pick up where he left off. Brewer would have been thrown into the fire and been forced to learn on the fly.
Experience: Fisher has played in more playoff games than any active player in the NBA today. He's won five championships and has a knack for knocking down big shots in big moments. Brewer, while playoff tested, doesn't have a résumé that can compare to Fisher's. Even in a results business, it has to be hard for a coach to not feel more comfortable with the guy who owns five championship rings.
Other options: Brewer has been likened to a bulkier Sefolosha since arriving in last month's trade. From that standpoint, Brewer might be seen as nothing more than a clone. If so, the coaching staff could simply feel more comfortable with the incumbent, as well as players like Russell Westbrook and Kevin Durant to provide perimeter defense in select spots.
Perimeter shooting: Brewer is a career 25.9 percent 3-point shooter. Fisher is a career 37.3 percent 3-point shooter. So while Brewer might be a better defender than Fisher, if Brewer is considered a clone the Thunder might want another shooter on the court to space the floor.