Watch Dee Gordon’s video apology, on the day he returns from his 80-game doping suspension

In April, when Dee Gordon was suspended for testing positive for two performance-enhancing drugs, he said in a prepared statement that he had ingested banned substances but “did not do so knowingly.”

He has served his 80-game suspension, and the Miami Marlins activated him Thursday. Gordon started at second base, batted leadoff and went hitless in four at-bats in a 5-4 loss to the St. Louis Cardinals.

In advance of his return, Gordon provided a apology on a video posted Thursday. He did not shed any light on why he used the substances or how he believed they got into his body. However, rather than claim he had used a contaminated supplement or had been prescribed a banned drug by an unaware doctor, Gordon took full responsibility.

“You’ve got to hold yourself accountable for your standards of living and training,” he said in the video. “I didn’t hold myself accountable for any of that. I thought I would never — being the smallest guy — would never fail a drug test. I didn’t pay attention at all, man. … That’s my fault and no one else’s.”

He added: “I let you down, and I’m sorry.”

Gordon, 28, won the National League batting and stolen-base titles with the Marlins last year, after the Dodgers had traded him in a six-player deal. The Dodgers traded Gordon and pitcher Dan Haren for pitchers Andrew Heaney and Chris Hatcher, catcher/infielder Austin Barnes and utilityman Enrique Hernandez, then flipped Heaney to the Angels for second baseman Howie Kendrick.

The Marlins signed Gordon to a five-year, $50-million contract in January. The contract is backloaded, so he lost about $1.5 million because of the suspension. He also is ineligible for postseason play this year.

bill.shaikin@latimes.com

Twitter: @BillShaikin