The Coliseum is gradually filling up, but there’s still plenty of empty seats in the second deck as we approach first pitch of the A’s-Yankees series opener.

A quick update of the day’s happenings:

–The A’s placed left fielder Conor Jackson on the DL with a strained right hamstring, not a surprise considering he had missed the past few games. His stint is retroactive to July 1, meaning he’s eligible to come off when the A’s resume play after the All-Star break. To bolster their outfield depth, the A’s called up Matt Carson and Matt Watson from Triple-A Sacramento and optioned right-hander Clayton Mortensen to Sacramento. Watson needed to be added to the 40-man roster, so Travis Buck was transferred to the 60-day DL. Pretty nice story for Watson, 31, who last played in the big leagues with the A’s in 2005. Since then, his journey has taken him to Japan as well as several minor league stops, but he’s back in the majors now.

–Coco Crisp went through pregame drills and his groin was OK, so he’s in the lineup tonight at leadoff.

–Check out tomorrow’s A’s notebook at contracostatimes.com for some reaction from Dallas Braden and Alex Rodriguez about A-Rod’s first return to the Coliseum since his infamous trot across the pitcher’s mound.

Tonight’s lineups:

A’s: Crisp CF, Barton 1B, Sweeney RF, Suzuki C, Cust DH, Kouzmanoff 3B, Gross LF, Ellis 2B, Pennington SS; Sheets RHP.

Yankees: Gardner LF, Jeter SS, Teixeira 1B, Rodriguez 3B, Cano 2B, Swisher DH, Granderson CF, Cervelli C, Curtis RF; Vazquez RHP.