Manager Bruce Bochy announced the Giants' plans Saturday, one day after Dodgers starter Paul Maholm hit Belt on the thumb with a fastball, causing the injury. Belt was scheduled to be examined by a hand specialist later Saturday in San Francisco.
To replenish their outfield depth with the imminent shift of Morse, their everyday left fielder, the Giants purchased the contract of Tyler Colvin from Triple-A Fresno. Second baseman Marco Scutaro, slow to recover from his strained lower back, was transferred from the 15-day disabled list to the 60-day DL. San Francisco also officially activated right-hander Matt Cain from the disabled list to start against the Dodgers and optioned right-hander George Kontos to Fresno.
Morse has appeared in 130 Major League games at first base, starting 100. He received his most extensive activity at first base with Washington in 2011, when he started 82 games at the position. He played seven games at first base last year for Seattle, starting six.
None of the other Giants considered for the sudden vacancy, most notably catchers Buster Posey and Hector Sanchez, has accumulated as much time at first base as Morse on the Major League level. Sanchez's first-base resume consists of one Cactus League outing. However, Bochy said that Posey and Sanchez probably will receive occasional starts at first base.
Posey played first base Saturday against Los Angeles, making his fifth start of the year at that spot. Bochy indicated that Morse will go to first on Sunday or Monday.
"We just think, for right now, this is the best way to go," Bochy said, pointing out that Morse rose through the Minor Leagues as an infielder. "... We're comfortable making this move."
"This will cut down on his 'quality starts,' " Bochy said, jokingly employing the term applied to starting pitchers who last six innings or more. Also, by keeping Morse on the field longer, Bochy won't have to worry as much about running out of reserve players.
Admitting that he never has seen Morse play first base and was relying on reports from scouts, Bochy indicated that the Giants won't hesitate to change their approach if the slugger struggles in the field.
Had third baseman Pablo Sandoval been chosen to be a more significant part of the first-base mix, the Minor Leaguer selected to join the Giants might not have been Colvin, but Adam Duvall, who has hit a team-high 11 home runs at Fresno, to go with a .259 batting average and a .541 slugging percentage.
"Duvall was talked about quite a bit," Bochy said.
Colvin, 28, likely will share left field with Blanco. Signed as a Minor League free agent during Spring Training, Colvin owns a .241 batting average with a .743 OPS (on-base plus slugging percentage) in 384 Major League games with the Cubs (2009-11) and Rockies (2012-13). A left-handed batter, Colvin hit .298 against right-handed pitchers and .267 overall in 35 games at Fresno.