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7/3/2013 9:21 P.M. ET

Straily to start Thursday, Parker pushed to Saturday

OAKLAND -- Jarrod Parker won't start on Thursday as planned, but the A's do have the right-hander penciled in for Saturday's game in Kansas City, giving him a few extra days to rest his tight right hamstring.

In Parker's place, righty Dan Straily will be recalled from Triple-A Sacramento on Thursday to pitch against the Cubs, putting in motion the likely optioning of catcher Stephen Vogt.

"It's just to give Jarrod a couple of extra days," manager Bob Melvin said. "He was feeling it a little bit yesterday, and last night when we went home we felt like the best thing to do would be push him back a couple days and make sure he's fine."

That gives Parker, who tweaked his hamstring in Saturday's start, a full week's rest. And Straily, optioned last week at the start of a stretch when the A's didn't need a fifth starter, was expected back Saturday, anyway. So, essentially, they're simply swapping rotation spots.

Had Parker not been available for an extended period of time, however, Melvin confirmed top pitching prospect Sonny Gray would've been called on to make his big league debut.

At the time of Straily's demotion, he was 4-2 with a 5.00 ERA in 12 starts. He has a career-high three-game winning streak over his last seven starts, but has tossed fewer than five innings in each of his last two.

"I think he's done enough this year, certainly, to be that guy," Melvin said. "You don't ever want to promise a young pitcher that when they go down that they're coming back on 'X' date, because you want to make sure he has an edge about him and goes out there and competes like he normally would. He's done some good things for us this year. The last couple of starts haven't been his best, but he was on quite a roll for us there, too."

Colon selected as AL's top pitcher for June

OAKLAND -- A's hurler Bartolo Colon continues to turn back time. For his latest efforts, the 40-year-old was given the American League Pitcher of the Month Award for June.

"I think there's gotta be a little specialness to it after the age of 40," manager Bob Melvin said. "He may not think it's a big deal, but I do."

Colon logged a 5-0 record and a 1.75 ERA in five starts during the month to capture his fourth such award and first since August 2005, the season he won the AL Cy Young Award. He led all qualifying starters in ERA and finished tied for second in wins, all the while padding his All-Star candidacy.

The right-hander averaged better than seven innings per start and allowed three runs or fewer each time out. He limited the Brewers to one run over seven innings, blanked the Yankees for six frames, held the Mariners to five runs across 15 innings in two starts and kept the high-powered Cardinals to one run over eight innings.

Colon, who was scheduled to face the Cubs on Wednesday, has posted an 11-2 record and a 2.79 ERA in 16 outings this year. He has earned the victory in eight consecutive starts, the longest such streak for Oakland since Barry Zito won eight straight in 2005.

"Like anybody, once you get on a little bit of a roll, you start to feel that much more confident," Melvin said. "The team feels confident about you, and maybe sometimes the results reflect that. But it doesn't really look like he's pitching any different than last year, maybe other than him mixing up his pitches a bit more."

Colon is the first Oakland pitcher since Dan Haren in May 2007 to win the monthly pitching accolade. He received the honor ahead of Detroit's Max Scherzer (5-0, 2.38 ERA), Baltimore's Chris Tillman (6-0, 2.68 ERA), Texas' Joe Nathan (11 saves, 0.63 ERA) and Kansas City's Ervin Santana (2-0, 1.99 ERA) and Greg Holland (nine saves, 1.38 ERA).

Jaso returns to starting lineup after 10-game respite

OAKLAND -- After being held out of the starting lineup for each of the last 10 games due to a left palm abrasion, A's catcher John Jaso was back in Wednesday against the Cubs.

"He feels good," manager Bob Melvin said. "He hit quite a bit yesterday and catching hasn't been the issue, so he feels good today."

Jaso is hoping to pick right where he left off before the injury, having hit .349 in June after combining for a .252 clip in April and May.

His return also means the A's, now equipped with three healthy catchers, will likely feel comfortable sending one of them -- likely Stephen Vogt -- back down to Sacramento on Thursday, when Dan Straily will be recalled to start against the Cubs.

Jane Lee is a reporter for MLB.com. Read her blog, Major Lee-ague, and follow her on Twitter @JaneMLB. This story was not subject to the approval of Major League Baseball or its clubs.