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5/20/2014 8:48 P.M. ET

No roster moves imminent despite Posey's injury

DENVER -- No roster moves are imminent, but if Buster Posey's stiff back were ailing him worse, the Giants probably would have to trim their 13-man pitching staff and add a catcher to provide a backup for Hector Sanchez, manager Bruce Bochy said Tuesday.

As matters stand, Posey, who was out of Tuesday's lineup and might sit out Wednesday due to nerve irritation in his lower back, could catch in an emergency.

Still, Bochy refused to leave anything to chance. "If Buster couldn't catch, we'd have to make a move," Bochy said.

Andrew Susac, the Giants' second-round selection in the 2011 First-Year Player Draft, and former Giants backup Guillermo Quiroz are the organization's top catchers at Triple-A Fresno.

Due to the respective ailments nagging Posey and center fielder Angel Pagan (left shoulder), the Giants began Tuesday's series opener against Colorado with two fully able-bodied reserve position players: infielders Joaquin Arias and Ehire Adrianza.

Hudson set to make start vs. Rox on Thursday

DENVER -- Right-hander Tim Hudson threw off a Coors Field bullpen mound without complications Tuesday, paving the way for him to start Thursday's series finale against the Colorado Rockies.

Hudson missed his scheduled start against Miami last Friday due to a strained left hip. But the ailment did not stop him from playing catch in the days immediately following the injury, indicating that the Giants' optimism surrounding the 38-year-old was well-founded.

Hudson, the Giants' most consistent starter this year, is 4-2 with a 2.09 ERA in eight starts. He's 5-2 with a 4.40 ERA in 12 career starts against the Rockies, including a no-decision this season on April 13. He lasted 7 1/3 innings in that one, allowing four runs and five hits. He's also 0-2 with a 7.41 ERA in six Coors Field starts.

Pagan feels good in batting cage, nears return

DENVER -- Center fielder Angel Pagan tested his sprained left shoulder by swinging in an indoor batting cage Tuesday, bolstering Giants manager Bruce Bochy's confidence that the leadoff hitter will rejoin the lineup Wednesday.

"He's doing a lot better," Bochy said. "I think he'll be fine to go tomorrow."

Pagan, batting .321 with an .810 OPS (on-base plus slugging percentage), sat out Sunday's series finale against Miami and received extra rest with Monday's scheduled off-day. After discussing Pagan's playing status with head athletic trainer Dave Groeschner, Bochy said they decided that another day off would further help the switch-hitter.

Pagan injured himself while attempting a diving catch Saturday against Miami.

Chris Haft is a reporter for MLB.com. Read his blog, Haft-Baked Ideas, and follow him on Twitter at @sfgiantsbeat. This story was not subject to the approval of Major League Baseball or its clubs.