Jose Guillen, a midseason pickup by the National League champion San Francisco Giants, has been linked to a federal performance-enhancing drug investigation, The New York Times reported on Thursday.

According to the Times, federal investigators informed Major League Baseball just prior to the start of the playoffs that they were looking into shipments of performance-enhancing drugs—including human growth hormone (HGH)—to Guillen’s wife at their Bay Area home.

Guillen, who came to the Giants from the Kansas City Royals in a trade for cash and a player to be named later on Aug. 13, hit .266 with three home runs and 15 RBI in 42 games.

Despite his relative lack of production, he was still expected to be named to San Francisco’s postseason roster. Surprisingly, fellow outfielder Aaron Rowand, who had struggled all season long, was named instead.

This could be why.

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