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2/16/2014 11:37 A.M. ET

Gonzalez pushes back 'pen session due to spasms

SARASOTA, Fla. -- Miguel Gonzalez will not throw his scheduled bullpen session on Sunday, as the O's right-hander -- who exited Saturday's workout with back spasms -- will give it another day or two to let the area calm down.

"My lower back tightened up a little bit on the rundown covering first [base]," Gonzalez said. "I haven't been stretching as much as I was used to. ... I feel pretty good now. I feel a lot better than I did yesterday."

Gonzalez, who threw a bullpen session on Friday, will continue to get treatment on the area and play it by ear in terms of getting back up on the mound. The right-hander had a minor back issue before one of his starts last year but was still able to pitch.

Britton working to improve command of sinker

SARASOTA, Fla. -- O's left-hander Zach Britton may not throw a regular bullpen session for a little while, and that's fine with him. The 26-year-old, who's at a pivotal point in his career, has been throwing to a plate with a pair of strings and a moveable target to help sharpen the command of his sinker ball.

The device, installed by new pitching coach Dave Wallace and bullpen coach Dom Chiti, is similar to what director of pitching development Rick Peterson had at the Minor League complex last year. There's a string at the bottom of the strike zone and a separate one at the top of the zone. The only difference from Peterson's device is the moveable target.

"Dom will go over there and move it to inside to [right-handed hitters] and say, 'Hey, let's throw your sinker. Figure out where you got to start that for it to end up in that box.' And vice versa, away to a righty," said Britton, who still throws a 30-35 pitch session. "That's the focus right now for them with me, is getting that sinker to a point where the command is there. It's not about throwing the offspeed yet. I think we all agree on when my fastball is there, all the rest of the stuff is there."

Out of Minor League options, meaning he would have to clear waivers if he doesn't make the club out of camp, Britton is competing for the fifth-rotation spot, and getting him back to his early 2011 form -- when he pitched to a 2.93 ERA in his first 11 big league starts -- would be a huge boon for the Orioles.

Britton, who again worked out in California this offseason with vice president of baseball operations Brady Anderson, has thrown three bullpen sessions already this spring. All have been with the strings.

"I think it was Zach's idea as much as theirs," manager Buck Showalter said. "I know [Kevin] Gausman has thrown over there, probably had everybody over there just I didn't know about it. They spent a lot of time putting that up. It was a lot of work on Dom and Dave's part. I walked over there one day, they were on their knees putting it in. Dom's perfected that."

Britton hopes to perfect his command, an issue that has caused a considerable amount of inconsistency since his first two months in the Majors. Bouncing between Triple-A Norfolk and the Majors, Britton pitched to a 4.95 ERA in eight games (seven starts) in the big leagues last season, and he went 5-3 with a 5.07 ERA in 12 games (11 starts) in 2012. He threw Saturday's bullpen session with Chiti overseeing and Steve Clevenger behind the plate, and Britton said he'll continue to use the optional device until he's satisfied with his command.

"It's all going to end up falling on Zach. Every pitch, being out of options affects them differently," Showalter said. "I think Zach knows there's a good chance he's going to be pitching for somebody in the big leagues this year. We hope it's us."

Brittany Ghiroli is a reporter for MLB.com. Read her blog, Britt's Bird Watch, and follow her on Twitter @britt_ghiroli. This story was not subject to the approval of Major League Baseball or its clubs.