OAKLAND -- While placing outfielder Conor Jackson on the 15-day disabled list on Monday with a strained right hamstring, the A's called up outfielders Matt Carson and Matt Watson from Triple-A Sacramento, optioning right-hander Clay Mortensen back to Triple-A.

Jackson's move to the DL was made retroactive to Thursday, and he said he hopes to be activated by July 16, the first day he's eligible to return.

"It's frustrating," Jackson said. "After missing so much time last year and missing 18 days from this year already, now this. But I'm not going to let it drag me down. I'm going to rehab and try to get back healthy as possible."

Jackson said he first strained his hamstring on June 17 at Chicago's Wrigley Field -- playing his third game with the A's after being traded by the Diamondbacks -- and aggravated the injury the next day in St. Louis. Jackson missed 18 games for Arizona -- spending time on the DL with a strained right hamstring from April 18-May 8 -- but he said the injury occurred in a different spot this time.

"I can swing the bat, but it's the running that gets me," Jackson said. "We'll do treatment for the next six or seven days, and hopefully by the All-Star break I can get out and maybe go down to Rookie [League] ball and play some games down there."

Mortensen, 25, made his 2010 debut in place of injured lefty Dallas Braden on Saturday, allowing four runs (three earned) over six innings, while striking out seven and walking two. Mortensen is 10-2 with a 3.58 ERA in 15 Triple-A starts this season and was recently named to the Pacific Coast League All-Star team.

Due to the next week's All-Star break and an off-day on Thursday, the A's can afford to go with four pitchers until the Midsummer Classic. Oakland is hoping Braden and fellow lefty Brett Anderson can return to the rotation shortly after the break.

Carson joins the A's for his third stint this year and entered Monday having gone 1-for-9 in four games so far. In 51 games with the River Cats, Carson was batting .301 with nine home runs and 29 RBIs.

"It's good to be back," Carson said.

Watson, 31, hasn't played in the Majors since 2005, when he batted .188 in 48 at-bats with Oakland. Watson remained with the A's Triple-A affiliate in '06 before heading to Japan and playing for manager Bobby Valentine and the Chiba Lotte Marines in '07.

Watson returned to America in 2008, playing for the Blue Jays' Triple-A affiliate in Syracuse, N.Y., before signing with South Korea's Doosan Bears in '09. He also played in the Mets farm system in '09 and with an independent league team in his hometown of Lancaster, Pa.

The A's signed Watson on May 28, and he hit .313 with eight home runs and 23 RBIs in 28 games with Sacramento.

"I always like the perseverance of a young man that keeps trying to get his opportunity in the big leagues and to keep that dream alive," said Oakland manager Bob Geren.

Neither Carson nor Watson was in the starting lineup against the Yankees on Monday, but Geren said Carson could be in the lineup on Tuesday against left-hander CC Sabathia.

Cahill's Sunday start would nix Classic

OAKLAND -- The way it's scheduled now, A's All-Star Trevor Cahill won't be making an appearance at the Midsummer Classic on July 13 in Anaheim.

The 22-year-old right-hander is 8-2 with a 2.74 ERA in 13 starts this season but is slated to start on Sunday against the Angels, making him ineligible to play during the All-Star Game.

Yankees skipper Joe Girardi, this year's manager for the American League All-Stars, was asked before Monday's game at Oakland what he plans to do if Cahill pitches on Sunday.

"We'll look at all of the players that are out there," Girardi said. "Trevor Cahill has thrown the ball extremely well. He'll still be an All-Star, and he'll still represent the A's there. If he pitches Sunday, obviously he won't be able to pitch, so we'll look at other guys."

Since Cahill is currently Oakland's lone representative this season, A's manager Bob Geren said he hopes the A's can have another player participate. Geren, who will be a coach for the All-Star Game, said he hadn't talked to Girardi as Monday afternoon.

Asked if he felt obligated to tab another A's player in Cahill's stead, Girardi said, "I think what you'll do is look at the most deserving pitcher to go next."

Geren has voiced his support for catcher Kurt Suzuki and a couple of A's relievers -- closer Andrew Bailey and lefty Craig Breslow. Bailey entered Monday having converted 17 of his 20 save opportunities this year, with a 1.59 ERA. Breslow, meanwhile, had a 2.84 ERA in 40 appearances this season. Suzuki entered Monday batting .255 with 35 RBIs and a team-high 10 home runs.

"I know Bailey's had a great year again, so I was kind of surprised it was me and not him," Cahill said. "But I think we have a lot of deserving guys on this team, and this year, I was lucky enough to go."

'Moneyball' filming sparks fond memories

OAKLAND -- It was the year of the streak, the year of Billy Koch and the year of "Moneyball."

The 2002 season was certainly a memorable one for the A's, and it will soon be immortalized on the silver screen. Fans wishing to relive the magical campaign will get their chance from July 25-Aug. 5, as the movie "Moneyball" will be filming at the Oakland Coliseum.

Among the current A's, only two are left from the 2002 team: Eric Chavez and Mark Ellis. As author Michael Lewis infiltrated the minds of Oakland's front office and players for his bestselling book, Ellis was a rookie second baseman.

For Ellis, no memory trumps the 20-game win streak Oakland put together in the second half of the season.

"Without a doubt, that's one of my favorite moments ever from baseball," Ellis said. "It was just a special time -- we just kept winning ballgames. It seemed like we got out to a 3-0 lead all the time, and if we did need a big hit late in the game, Miguel Tejada was getting the big hit for us. It was a really incredible time."

The A's ended their streak in style, earning their 18th, 19th and 20th wins in their final at-bat. First was Tejada's three-run homer off then-Twins closer Eddie Guardado to win No. 18, then Tejada delivered a game-winning single off Kansas City's Jason Grimsley in the ninth inning for consecutive win No. 19.

First baseman Scott Hatteberg saved the best for last with a dramatic pinch-hit solo homer off Grimsley to give the A's a 12-11 win on Sept. 4, 2002, their 20th in a row. Ellis was in the on-deck circle to witness Hatteberg's blast.

While Oakland's "Big Three" of Barry Zito (23-5, 2.75 ERA), Tim Hudson (15-9, 2.98 ERA) and Mark Mulder (19-7, 3.47 ERA) were consistent all year, Koch -- the A's closer in 2002 -- often made things interesting in the ninth inning.

Koch went 11-4 with 44 saves and a 3.27 ERA in 2002 but earned five victories after blowing a save, including the team's 20th straight win.

"He was an awesome teammate," Ellis said of Koch. "He had a lot of personality, a lot of life. He was kind of like the way he was like as a closer -- he would walk the bases loaded and then get three strikeouts."

Though the A's eventually lost to the Twins in the American League Division Series, Tejada won the AL MVP Award, Zito won the AL Cy Young Award and the late Cory Lidle shined in the second half.

Brad Pitt will play the role of general manager Billy Beane in the movie, while Jonah Hill will be assistant general manager Paul DePodesta and Philip Seymour Hoffman will play manager Art Howe.

Worth noting

A's left-hander Brett Anderson threw 20 pitches on Sunday -- all fastballs and changeups -- in a simulated game in Arizona. Manager Bob Geren said that Anderson, who hasn't pitched in a game since June 3 due to left elbow inflammation, reported no setbacks and that the A's are still hoping he will return shortly after the All-Star break. "His mechanics and everything looked good," Geren said.