The A's announced Friday that they have designated left-hander Travis Blackley and first baseman Daric Barton for assignment, meaning they have been moved off the 40-man roster and must be traded, released or accept an assignment to the minor leagues within the next 10 days.

In other moves made by the A's on Friday, left-handed reliever Jordan Norberto was optioned to Triple-A Sacramento, and righty relievers Danny Otero and Josh Stinson were claimed off waivers from the New York Yankees and Milwaukee Brewers, respectively. Otero began spring training with the Giants before being claimed off waivers by the Yankees on Tuesday.

Blackley had a nice season for the A's last year, going 6-4 with a 3.86 ERA in 15 games, including 15 starts. But he was brutal in spring training, posting a 14.21 ERA and allowing 27 hits in 12¿2/3 innings. Opponents hit .450 against him.

Barton was hitting .206 in spring training, two points above what he hit in 46 games for the A's last season. Coupled with the fact that he has little power, Barton also became dispensable despite being a pretty good defensive first baseman.

Otero pitched in 12 games for the Giants last season, compiling a 5.84 ERA. Stinson had an 0.96 ERA last year for the Brewers, but the sample size was small as he pitched in six games.

The A's have 32 players in camp including starting pitcher Bartolo Colon, who will miss the first five games of the season to compete a 50-game suspension for using performance-enhancing drugs. That means the A's will have to trim six more players before the season-opener Monday against Seattle at the Coliseum.