Colin Kaepernick's arm strength and conditioning stood out in his workout with the Las Vegas Raiders, but no signing was imminent as of late Thursday night, sources told ESPN.

The Raiders considered Kaepernick's workout a "positive," a source said. Las Vegas could be looking for another passer to serve as the backup for Derek Carr despite trading for former New England Patriots quarterback Jarrett Stidham and signing Nick Mullens.

Kaepernick, 34, hasn't played in the NFL since 2016, the year he began protesting racial inequality during the national anthem. The only other team known to have brought him in for a visit since then was the Seattle Seahawks in May 2017.

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Kaepernick recently threw to undrafted receivers for NFL scouts at halftime of Michigan's spring game, at the invitation of Jim Harbaugh, his former coach with the San Francisco 49ers.

LOOK: 50 images of winning moments from sports history

Sometimes images are the best way to honor the figures we've lost. When tragedy swiftly reminds us that sports are far from the most consequential thing in life, we can still look back on an athlete's winning moment that felt larger than life, remaining grateful for their sacrifice on the court and bringing joy to millions.

Read on to explore the full collection of 50 images Stacker compiled showcasing various iconic winning moments in sports history. Covering achievements from a multitude of sports, these images represent stunning personal achievements, team championships, and athletic perseverance.