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8/15/2013 3:42 A.M. ET

A's being cautious with Jaso's recovery

OAKLAND -- A's catcher John Jaso is expected to make a full recovery from the concussion he experienced in late July, but the timetable for his return is still up in the air.

Jaso met with Dr. Michael Collins, a leading authority on concussions, in Pittsburgh on Tuesday after the team decided his prolonged inability to participate in baseball activities garnered cause for a consultation.

The left-handed hitter has already been cleared for physical activity, such as weight lifting, riding a stationary bike and running on a treadmill, but baseball activities are still out of the question after meeting with Collins.

"He said that he's going to be fully recovered from this, just not that this point," A's manager Bob Melvin said.

The next step for Jaso is to work on visual exercises, but because of the nature of head injuries, it's difficult to assess when he'll be able to resume a more strenuous workload.

When asked whether Jaso returning to the field this season was in question, Melvin could not say for certain.

"We certainly hope not," he said. "But again, there's no timetable at this point."

Melvin earns fourth ejection of season

OAKLAND -- A's manager Bob Melvin was ejected from Wednesday night's 2-1 loss to the Astros after arguing a call with second-base umpire Doug Eddings after the third out of the eighth inning.

Melvin approached Eddings after Eric Sogard was called out at third on an attempt to tag from second base on Nate Freiman's fly ball to center field. Brandon Barnes' throw was ruled to beat Sogard, prompting a demonstrative protest by Sogard and Melvin's emergence from the home dugout.

"We got to make sure we're safe," Melvin said on Sogard's decision to tag up. "The debate is whether he was safe or not."

Equally questionable was Alberto Callaspo's attempt to bunt with Sogard on second once again with no one out in the 11th. Callaspo had failed his attempt to lay down a clean bunt earlier in the game, and he did so again in the 11th, popping up for the first out of the inning before Jed Lowrie and Josh Reddick struck out in consecutive at-bats to end the game.

"It just seemed like it was frustrating from the beginning and it got more frustrating as the game goes along," Melvin said. "You got to try to put that away and keep your wits about you. It's one of the more frustrating losses of the year."

The ejection was Melvin's fourth of the season and 29th in his managerial career.

Norris expects to be behind the plate Thursday

OAKLAND -- Derek Norris is still on pace to start at catcher for the A's in Thursday's series finale against the Astros as he continues to recover from back spasms that made standing up a challenge just three days ago.

Norris was available for "emergency use" on Tuesday but did not play, though A's manager Bob Melvin said he was more likely to be a "useable piece" on Wednesday.

Norris caught a bullpen session on Tuesday and felt good after, and he took batting practice prior to Wednesday 's game. Assuming all goes well, Norris will start Thursday to provide an extra right-handed bat against Astros left-handed starter Erik Bedard.

"Obviously, my back's not 100 percent," Norris said. "But I'm able to do every movement without any pain. It's just a little bit of back tightness and that's it."

Melvin opted not to pinch-run for Tuesday's starting catcher, Stephen Vogt, when he reached first base in the ninth inning with the A's trailing by one run, but the A's manager said that was more because of Oakland's limited bench than Norris' health.

Melvin inserted Coco Crisp to pinch-run for first baseman Nate Freiman in the eighth, which resulted in a everyday third baseman Josh Donaldson switching to first base on defense in the ninth and Alberto Callaspo coming into the game to play third base.

"I had no one to pinch-run for him," Melvin said.

Colon battling worst funk of comeback season

OAKLAND -- It's difficult to gauge the amount of concern there should be following Bartolo Colon's second poor start in as many outings.

Colon has stepped in as Oakland's ace this season with Brett Anderson on the disabled list and has had perhaps his best season since receiving the 2005 American League Cy Young Award, winning 14 games with a 2.97 ERA in 25 starts this season.

Yet he hasn't made it past the fourth inning in his last two outings. He gave up five runs in four innings on Tuesday against the Astros and has allowed 10 earned runs in his last 6 2/3 innings after allowing just nine in his previous 49 1/3.

Colon's funk is particularly concerning because of his age. The 40-year-old is on pace to pitch his most innings since '05, and his velocity has dropped in his last handful of starts.

The drop in velocity of his fastball -- easily Colon's most prevalent pitch -- has resulted in less movement. At his best, the right-hander's fastballs quiver around the plate, but on Tuesday many found the heart of strike zone and resulted in seven hits and his exit after 77 pitches.

"I don't think he's thrown this many innings since '05 or '06, I believe, so yeah, you continually monitor that," A's manager Bob Melvin said. "You know, it is what it is as far as [age] goes, and we'll just continue to monitor each and every outing."

Melvin said there are no plans for Colon to skip a start or receive extra rest before his next outing, adding that such a move might not make a difference.

Colon's start against the Reds on Aug. 7 followed more than the typical five days' rest, yet ended after 2 2/3 innings -- his shortest of the season -- when, once again, the opposing batters tagged him for five runs on seven hits.

"I don't know if that would really, at this point in time, help him that much," Melvin said. "We've talked to him some. He had seven days before the previous one to this one, I think Cincinnati. If he feels like he needs it, we'll certainly try to stay communicative with about him with that. He's just going through a rough patch right now."

Crisp limited to pinch-running while wrist heals

OAKLAND -- A's outfielder Coco Crisp received a cortisone injection Tuesday night to help relieve the pain in his left wrist and he will be unavailable to hit for a handful of games.

While the A's hope the shot will accelerate the healing process, manager Bob Melvin said it would also result in Crisp's inability to swing a bat for "a day or two."

"It had been lingering a little bit and we felt like this was probably the best course of action to speed up the recovery," Melvin said.

Oakland's leadoff man and center fielder injured his wrist while making a diving backhanded catch in Sunday's contest against the Blue Jays. He was inserted into the eighth inning of Tuesday's series-opening loss against the Astros as a pinch-runner and was available to do so again Wednesday.

Jeff Kirshman is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.