SAN FRANCISCO -- At one time, Giants pitcher Shaun Anderson was baseball's equivalent of the NFL's Mr. Irrelevant.

Anderson was the 1,216th and final pick in the 2013 Draft, selected by the Washington Nationals. He opted not to sign with the Nats and instead decided to play college ball at Florida.

Now the 24-year-old right-hander, who was Monday night's starting pitcher in a 5-4 exhibition loss to the Oakland A's at Oracle Park, is the top-rated pitching prospect in the Giants' farm system. He was acquired by the Giants in 2017, when infielder Eduardo Nunez was dealt to the Red Sox, whom Anderson signed with after being taken in the third round of the 2016 Draft.

The Giants were going to start left-hander Drew Pomeranz on Monday night, but manager Bruce Bochy will go with Pomeranz and Jeff Samardzija in Tuesday night's final exhibition. The Giants open the regular season Thursday in San Diego.

Bochy's decision to start Anderson raised some questions about the order of the Giants' rotation. In a normal five-man rotation, Monday night's starter would have pitched Saturday in San Diego. If both Pomeranz and Samardzija pitch an inning or two Tuesday, it's possible Bochy could go with the pitcher of his choice Saturday.

"I would like to wait a day," Bochy said after Monday's game. "I'll talk to you guys tomorrow about that."

No matter what decisions are announced Tuesday, they won't involve Anderson, who will start the season at Triple-A Sacramento.

Anderson gave a reasonably good account of himself during his three innings.

After a rocky first inning in which he gave up a one-out walk to Matt Chapman, a single to Stephen Piscotty and an RBI hit to Jurickson Profar, Anderson settled down, retiring the last seven batters he faced.

"He did a nice job," Bochy said. "His pitches have nice movement and a lot of life. He'll be one of those guys in Sacramento that could help us at any point [in the season]. He will be a starter in the Major Leagues."

Anderson said he didn't get a chance to play catch before the game because of the wet weather. That caused him to take a little time to get a feel for his pitches.

"By the second inning, I felt pretty good," said Anderson, adding that he went along with whatever pitches catcher Buster Posey was calling for.

Asked about being the final pick in the 2013 Draft, Anderson said he took a pretty good ribbing. He said he never considered signing with the Nationals.

"The Nationals called, told me they drafted me and said they wanted to follow me over the summer," Anderson said.

But he knew he was going to sign a letter of intent with Florida, and three years later that decision paid off when he was drafted by the Red Sox.

Giants deal Stratton
After the game, the Giants announced they had dealt pitcher Chris Stratton to the Angels for left-hander Williams Jerez.

Jerez, 26, made 17 relief appearances for the Angels last year, logging a 6.00 ERA. It was his first season in the Majors.

He pitched in eight games for the Angels this spring, allowing two runs in 7 1/3 innings.

Stratton was 15-14 with a 4.63 ERA in 48 games for the Giants over the last three seasons.

Questions in the outfield
The Giants still appear to be unsettled in the outfield. Steven Duggar is likely to start the season in center and Gerardo Parra will probably play right.

That makes Mac Williamson the odds-on favorite to play left. He leads the Giants in at-bats with 59 this spring, but is hitting just .237 with one homer and five RBIs. He's walked twice and struck out 18 times.

The Giants went with Michael Reed in right field and Connor Joe in left against the A's on Monday.

"We have some options on what to do," Bochy said. "We had a couple of young kids out there tonight. It has not been decided what we will do."

Reed, who was acquired from the Twins, raised some eyebrows Monday night when he threw out Mark Canha going from second to third on Chad Pennington's fly out in the seventh. He was 0-for-3 at the plate with a walk and scored a run.

Joe, obtained from the Reds on Thursday, also played first base in his first start for the Giants. He singled in three at-bats with a walk, a run and a stolen base.

Later in the game, Henry Ramos, who took over in left when Joe moved to first, threw out Chad Pinder trying to stretch a single into a double.

None of the three outfielders -- Reed, Joe or Ramos -- is considered to be more than a backup. Ramos was signed as a Minor League free agent after spending nine seasons in the Red Sox and Dodgers farm systems.

New catcher in camp
The Giants continued to shuffle backup catchers Monday, claiming Tom Murphy from the Rockies and optioning Aramis Garcia to Triple-A Sacramento.

The Giants are expected to have just two catchers on their 25-man roster when they open the regular season Thursday in San Diego. That means Murphy or Erik Kratz, who joined the Giants on Sunday after being acquired from the Brewers, will back up Posey. Kratz went 1-for-2 with a two-run single in Monday's game.

Murphy, who turns 28 on April 3, has made brief appearances with the Rockies in each of the past four seasons. He never played in more than 37 games or had more than 93 at-bats in a season for the Rockies. He has decent pop with 10 homers in 196 Major League at-bats, but his average is .219 and he has struck out 82 times.

Murphy singled in two at-bats and scored a run Monday night.

Garcia, 26, rated as the Giants' 22nd-best prospect by MLB Pipeline, had a cup of coffee in San Francisco last season, appearing in 19 games. He hit .286 with four homers in 63 at-bats, but he struck out an alarming 31 times. He was hitting .216 with two homers this spring.

Garcia is the second-best catching prospect in the Giants' system, behind Joey Bart, the organization's top prospect and expected eventual successor to Posey.