Purchased the contract of right-handed pitcher Juan Gutierrez and infielder Brandon Hicks.  • Reassigned outfielder Tyler Colvin to Triple-A Fresno and right-handed pitcher Derek Law to Double-A Richmond.  • Left-handed pitcher Jeremy Affeldt (right knee sprain) retroactive to March 23 and infielder Marco Scutaro (lower back strain) retroactive to March 21, have been placed on the 15-day disabled list.  • Outfielder Roger Kieschnick was designated for assignment.  Bruce Bochy said he’ll use somewhat of a platoon at shortstop, meaning Brandon Crawford won’t play regularly against left-handed pitchers.  “It’s not going to be a straight platoon,” said Bochy, adding Crawford will face some lefties. “His at-bats will determine how much.”  Joaquin Arias will be the Opening Day second baseman. But for the most part, when lefties pitch, Arias will move over to short and Brandon Hicks would play second.  Bochy set his 25-man roster, and here are some highlights:  Juan Perez is the No. 5 outfielder, so Tyler Colvin, who was limited in spring training with a back ailment, will open at Triple-A Fresno.  Juan Gutierrez won the final bullpen spot, meaning Derek Law will open with Double-A Richmond.  Left-handed reliever David Huff and backup infielder Ehire Adrianza won jobs.  Gutierrez and Hicks were added to the 40-man roster, and outfielder Roger Kieschnick was designated for assignment.  Second baseman Marco Scutaro (lower back strain) and Jeremy Affeldt (right knee sprain) were placed on the disabled list.  The roster includes five starters (Madison Bumgarner, Matt Cain, Tim Hudson, Lincecum and Vogelsong), seven relievers (Sergio Romo, Santiago Casilla, Javier Lopez, Jean Machi, Yusmeiro Petit, Gutierrez and Huff), two catchers (Buster Posey and Hector Sanchez), six infielders (Brandon Belt, Arias, Crawford, Pablo Sandoval, Hicks and Adrianza) and five outfielders (Michael Morse, Angel Pagan, Hunter Pence, Gregor Blanco and Perez).  Here’s the lineup Bochy plans to use Monday in Arizona (righty Brandon McCarthy will start for the Diamondbacks):  I asked the manager what happened between Thursday and Friday — Thursday, he seemed set on Pence as the No. 2 hitter, but he said Friday Belt would hit second against righties.  “That’s the thing about managers, they can change their mind,” Bochy said.  Another thing: the Giants were shut out in the game Pence hit second, though he got two hits.  A day after taking a sharp liner off the inside of his left knee, Lincecum anticipated making his scheduled start Thursday in Arizona. He was diagnosed with a bruise after x-rays were negative.  “I’ve got to listen to them,” Lincecum said of Giants trainers, “but right now I feel I should be fine.”  The two-time Cy Young Award winner said he felt about the same as he did Friday, but he walked around the clubhouse and rode a stationary bike without favoring the knee.  Bochy was glad to see it.  “He’s doing fairly well,” he said. “I think we’re pretty comfortable he’ll be OK to go. We’ll keep an eye on him.”
Starters (5):
 
 LH Madison Bumgarner
 
 RH Matt Cain
 
 RH Tim Hudson
 
 RH Tim Lincecum
 
 RH Ryan Vogelsong
 
 Relievers (7)
 
 RH Sergio Romo
 
 RH Santiago Casilla
 
 LH Javier Lopez
 
 RH Juan Gutierrez
 
 LH David Huff
 
 RH Jean Machi
 
 RH Yusmeiro Petit
 
 Catchers (2)
 
 Buster Posey