Carroll made his decision after watching Wilson compete at the team's just-completed three-day rookie minicamp. The Seahawks coach said Russell took 500 snaps and threw approximately 400 passes during the three days.
"He's showed us enough," Carroll told reporters. "He's in the competition. And that is going to tax us, as you know. It was already going to be taxing with two. But he's shown us enough that we need to see where he fits in with these guys."
The Seahawks drafted Wilson out of Wisconsin in the third round of this year's draft. Flynn, a former Green Bay Packers backup, signed a three-year, $26 million contract with $10 million guaranteed earlier this offseason. Jackson started much of last season.
Carroll said deciding on a starting quarterback will be a long process.
"It's going to take us a long time to do this," he told reporters. "It's going to be frustrating for [the media]. You're going to keep asking and want to know. I'm just going to be more patient than you can imagine as we go through this process, and we'll just figure it out when we do."
Information from The Associated Press was used in this report.