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7/10/2014 7:28 P.M. ET

'Tough-minded' Vogt showing off strong bat

SAN FRANCISCO -- No matter where he's playing in the field, Stephen Vogt just keeps hitting.

Since his June 1 promotion, the A's Vogt has manned four positions, while maintaining a .367 average and .925 OPS (on-base plus slugging percentage) over 31 games -- including a .400 average against right-handers.

On Thursday he made his third consecutive start at first base, following three straight days in right field. He caught the day before that.

"It shows you that he's a pretty tough-minded guy," said manager Bob Melvin. "It's one thing to say, 'Hey, I'm a pretty versatile guy, you can move me around.' But to do it at the big league level and move to different positions on a day-to-day basis, and when you're just getting here, too, shows you a little bit about his tenacity.

"He's a very tough kid who always expects to succeed, and there's nothing you can throw at him that you feel like you're asking too much of him."

Vogt extended his career-high hitting streak to 10 games Thursday by going 2-for-5 with three RBIs. He's batting .457 with five multi-hit games during the streak.

"His bat stays in the zone for a while," said Melvin. "He's not afraid to stick his nose in there. He's quick, where he can react to pitches inside, and has really come a long way with being able to hit some offspeed pitches. Earlier, I think he was more thought of as a fastball hitter, where now he's letting the ball travel some and is doing some damage with breaking balls, too."

Day off comes at good time for banged-up Crisp

SAN FRANCISCO -- Coco Crisp was out of the A's lineup for Thursday's finale in San Francisco after slightly twisting an ankle in Wednesday's loss.

Manager Bob Melvin said he was probably going to give the veteran the day off anyway. Crisp has had a lot of those in the first half of the season, starting just 60 of the club's 92 games as a result of various injuries and completing only 49 of them.

"As hard as he plays, as I've said often, we're going to be careful with him," Melvin said before Thursday's game. "This off-day was probably there either way, but when you see him get banged up like he did yesterday, I'm thinking in my head before the game's even over that today's probably going to be a day to give him off."

Crisp was extended through the 2016 season in the winter -- but only after the A's gave up former top outfield prospect Michael Choice to acquire Craig Gentry from the Rangers.

Gentry, who entered the day batting .400 over his previous five games, made his 26th start in center field in Crisp's stead Thursday.

"That's the reason you give up a Michael Choice, to get a guy like him that can do that," Melvin said. "He's a very good in-game player, too, even when he doesn't start, but it's easy when Coco gets a day off to throw him out in center field. You know you're going to get a guy that's going to make the pitcher work, and he's going to play center field as well as anybody in the league."

Umpire Johnson departs with possible concussion

SAN FRANCISCO -- Home-plate umpire Adrian Johnson exited Thursday's game between the A's and Giants at AT&T Park after just three innings because of a possible concussion resulting from a foul tip to his mask.

Crew chief Angel Hernandez, who began the contest at second base, took over duties behind the plate, leaving just a pair of umpires in the field.

Johnson took a hard foul tip off the front of his mask during Pablo Sandoval's first-inning at-bat. According to umpire supervisor Ed Montague, Johnson was being examined for concussion symptoms.

Worth noting

• Outfielder Josh Reddick (right knee) is expected to begin a Minor League rehab assignment this weekend and continue it through the All-Star break with Class A Advanced Stockton.

Jane Lee is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.