SAN FRANCISCO -- The Giants are down to a three-man rotation after optioning Conner Menez to Triple-A Sacramento following his shaky start against the Phillies on Sunday. 

Menez's demotion, coupled with the injury to Shaun Anderson, leaves Madison Bumgarmer, Jeff Samardzija and Tyler Beede as the only starters on the current 25-man roster. 

The Giants called up catcher Aramis Garcia from Triple-A Sacramento to fill Menez's roster spot Tuesday, giving them another right-handed bat to deploy against A's left-hander Brett Anderson in the Bay Bridge Series opener, but they'll need to fill two rotation spots during their upcoming four-game series in Arizona. 

"We're talking about all our options right now," manager Bruce Bochy said. "We'll come up with it soon."  

Bochy said Dereck Rodriguez and pitching prospect Logan Webb, who fired seven innings of one-run ball in his Triple-A debut Monday, are candidates to fill the voids in the rotation. Andrew Suarez, who is currently pitching out of the Giants' bullpen, could also start.  

Anderson, who landed on the injured list last week with a blister on his right middle finger, threw a bullpen session Tuesday, but he will not be eligible to be activated until Sunday. 

Sandoval ailling

The Giants placed infielder Abiatal Avelino on the taxi squad Tuesday as they continue to monitor Pablo Sandoval, who is dealing with inflammation in his right elbow. Bochy said Sandoval can hit left-handed, but his elbow flares up when he swings or throws from the right side. The 33-year-old utility player was scheduled to be evaluated after batting practice to determine his availability for Tuesday's game. 

Worth noting 

• Alex Dickerson (right oblique strain) began a rehab assignment with Triple-A Sacramento on Tuesday. He was due to take three to four at-bats as a designated hitter for the River Cats. Bochy said Dickerson will rejoin the Giants on Wednesday and be reevaluated, as Sacramento is scheduled to hit the road later this week.

"Not saying we're going to activate him, but we'll at least evaluate him," Bochy said.

• Johnny Cueto (Tommy John surgery) is set to make his third rehab start with Class A Advanced San Jose on Thursday. Cueto is set to throw approximately 45 pitches over three innings.

• Bochy said Steven Duggar is still weighing treatment options for the sprained AC joint in his left shoulder and will seek out a third opinion. Duggar, who is likely out for the rest of the season, previously said he was leaning toward undergoing surgery, which would entail a three-month recovery period.