SAN FRANCISCO — Giants closer Hunter Strickland broke his pitching hand punching a door in frustration after blowing the save and taking a 5-4 loss to Miami on Monday night.

The right-hander was undergoing surgery Tuesday and expected to be out 6-8 weeks, Manager Bruce Bochy said. An X-ray after the game revealed the break of Strickland’s pinkie, similar to what sidelined lefty ace Madison Bumgarner to begin the season after he was hurt in his final spring training start.

Bochy says he is “thoroughly disappointed, I’m crushed” because Strickland had shown maturity and made progress keeping his emotions in check since last year’s fight with Nationals star Bryce Harper.

ORIOLES: Pedro Alvarez was designated for assignment by Baltimore, which made several moves Tuesday in an attempt to improve a team with the worst record in the big leagues.

The 31-year-old Alvarez had a .181 batting average with eight home runs and 18 RBI in 45 games. Used mostly as a designated hitter, he was in a 1-for-18 skid since his last multihit game, on May 24.

As a corresponding move, the Orioles selected the contract of infielder Steve Wilkerson from Triple-A Norfolk, whose first appearance will be his major league debut. In December, Wilkerson received a 50-game suspension for a violation of the Minor League Drug Prevention and Treatment Plan.

In addition, Baltimore recalled catcher Caleb Joseph from Norfolk. Joseph began the season as the Orioles’ starting catcher but was optioned to the minors on May 17 after batting .182 in 24 games.

CUBS: The routine act of taking off a pair of pants early Monday morning caused closer Brandon Morrow to suffer back spasms that prevented him from pitching the ninth inning of the Cubs’ loss to the Dodgers in the first game of Tuesday’s split doubleheader.

“I was taking my pants off after getting home at 3 a.m.” Morrow said as the Cubs returned late from St. Louis. “Got my right leg off. My left one, I felt spasms in my back.”

Morrow, who has converted 16 of 17 save chances, believes the ailment isn’t serious, adding his range of motion has improved.

RANGERS: Texas optioned rookie left-hander Yohander Mendez back to Triple-A Round Rock for violating team rules.

Mendez was supposed to start Wednesday against Kansas City.

General Manager Jon Daniels says at least one other player was involved, but discipline will be handled in-house. He says the incident is “not criminal, nothing involving MLB or the police.”