The Toronto Blue Jays, Houston Astros, New York Yankees, Boston Red Sox, and Los Angeles Dodgers all reportedly had scouts in attendance for Gray's start Friday, according to Susan Slusser of the San Francisco Chronicle.
While it's possible the scouts could have been watching other players, those in attendance to see Gray received a strong performance. The 2015 All-Star dazzled over six shutout innings against the Cleveland Indians, allowing just two hits and one walk while striking out five.
Speaking of the Indians, sources tell ESPN's Buster Olney they're also among the teams evaluating Gray.
Slusser also reported that the Chicago Cubs are among the teams with significant interest in Gray despite recently adding Quintana, though they didn't have a representative in the scouts' section for the start.
Gray is arguably the Athletics' best trade chip. He's 5-4 with a 3.72 ERA, 1.16 WHIP, and 79 strikeouts over 84 2/3 innings this season and has posted a 1.33 ERA over his last four starts, with opponents hitting just .122/.168/.244.
Another factor making the 27-year-old attractive for suitors is that he's under team control through 2019.