Bochy draws out suspense on naming No. 5 starter

The Giants’ fifth starter?

Matt Cain or Ty Blach? Manager Bruce Bochy let the mystery linger Thursday. He said he had a pretty good idea of who it will be, but would announce the decision Friday.

Most likely: Cain. His spring ERA was 7.82, but his last two outings were encouraging. Blach’s ERA was 4.43. Not that this will be the decider, but Cain will be paid $20.8 million this season. Walkman: Brandon Belt batted second Thursday against the A’s at AT&T Park. Is that Bochy’s plan for the season?

“Yeah, that’s the way I’m leaning right now,” Bochy said. “We did it last year; he’s a good on-base guy . ... I said I’m going to put him in the two hole because that’s his thing; he gets on base.”

In seven games plugged into the two-hole last season, Belt’s on-base percentage was .500 (.394 for the whole season). Take it easy, kid: General manager Bobby Evans took pains to explain why Jarrett

Parker should not feel pressured as he opens the season as the left fielder.

“The weight of our lineup will never be on whoever’s in left field, it’s really on the veteran guys,” Evans said. “They’re going to carry the day, and hopefully the left fielder does his part. We’re only as strong as the core of our lineup, (so) the left fielder ... doesn’t have the world on his shoulders.” Favorable impression: Third baseman Jae-gyun Hwang will open the season at Triple-A Sacramento, playing left field and first base, to increase his versatility.

“If he continues doing this in Sacramento, with that bat, you’ve got to find a spot for him,” Bochy said of Hwang.

No spot: Infielder Jimmy Rollins was informed that he did not make the roster. The Giants are waiting to hear from Rollins and his agent, though it appears unlikely the Alameda native will accept an assignment to the minors.

B-Craw’s backup: Eduardo

Nuñez played third. Bochy said Nuñez’ injured right shoulder is fine, and he will play a few innings at short in this three-game Oakland series. Said Bochy, “He could be the guy playing short when

(Brandon) Crawford gets a day.”

No bullpen fireman: Bochy’s oldest son Greg is in the San Francisco Fire Department academy, hoping to move up after beginning his firefighting career with the Woodside department. Greg played two years of minor-league ball.