ALAMEDA — Raiders cornerback Dominique Rodgers-Cromartie announced his retirement on social media Tuesday, a move confirmed by a team source.

Rodgers-Cromartie, 32, went from 55 snaps on defense in London against Seattle to zero in a 42-28 loss to the Indianapolis Colts. He signed at the start of the regular season when the Raiders were looking for veteran help at cornerback after it was learned Daryl Worley had been suspended for four games for being in violation of the NFL’s policy on substance abuse.

The Raiders also played rookie fourth-round pick Nick Nelson (21 snaps) at cornerback for the first time this season against Indianapolis and are hoping to increase his playing time.

Included on a message posted on Rodgers-Cromartie’s Instagram account: “Today my NFL journey ends ... I’m at peace with my decision ... Y’all may not understand and that’s kool!!!”

The NFL Network’s Ian Rapoport confirmed with Rodgers-Cromartie through a text message that he was retiring.

Worley and Gareon Conley got the bulk of playing time for the Raiders against Indianapolis while Cromartie played 22 snaps on special teams and none in the secondary. A potential role as a safety never evolved. The Raiders went primarily with Marcus Gilchrist, Erik Harris and Karl Joseph at safety against the Colts.

Taking a seat against Indianapolis were starting free safety Reggie Nelson, who had started 38 consecutive games, and cornerback Rashaan Melvin, an offseason free agent signing who had played extensively.

Asked Monday if the fluctuation in play of the cornerbacks and secondary could hurt the confidence and comfort level of those involved, coach Jon Gruden said, “It can be. It can also be an excuse. It can be a lot of things. We’re looking for more consistency. We’re looking for somebody to step up, not only on game day but during the week.”

A popular veteran, Rodgers-Cromartie bought Raiders jackets with British flags on one arm for his teammates and support staff before the team went to London.

Rodgers-Cromartie was credited with six tackles, according to the Raiders’ statistics, with two passes defended and a forced fumble. He has 30 career interceptions in a career that began with the Arizona Cardinals (2008-10) and continued with Philadelphia (2011-12), Denver (2013) and the New York Giants (2014-17).

With the NFL trading deadline arriving at 1 p.m. Tuesday, the Raiders were reportedly shopping defensive end Bruce Irvin and Joseph, but those moves never materialized.