Kenley Jansen prevails despite wobbly relief role for Dodgers

The Dodgers encountered an unexpected scare Sunday, as Kenley Jansen served up a three-run home run in the ninth inning before closing out a 4-3 victory over the Arizona Diamondbacks at Chase Field.

Jansen entered the game with a four-run advantage he inherited from starter Zack Greinke and began the inning by striking out A.J. Pollock and Ender Inciarte.

“Kind of took it a little for granted when I got to two outs,” Jansen said.

Jansen walked Paul Goldschmidt, gave up a single to David Peralta, then served up a home run to Jarrod Saltalamacchia.

Suddenly, the Dodgers’ lead was down to one run.

After a chat on the mound with Manager Don Mattingly, Jansen settled down and struck out Jake Lamb to end the game.

“I’ve got to finish the inning,” Jansen said. “I didn’t do that. That shouldn’t happen.”

Jansen was also called on to protect a four-run lead the previous night, as Mattingly was reluctant to turn the game over to one of his less reliable pitchers in a hitter-friendly ballpark.

“I’m not going to let anything get going,” Mattingly said. “Four runs in this ballpark is not that much.”

Back to the bullpen

Mat Latos, who was scratched from his previous start because of neck problems, will pitch out of the bullpen for now.

Latos has been a disappointment since the Dodgers acquired him from the Miami Marlins at the July 31 non-waiver trade deadline. He has failed to pitch five innings in each of his last four starts.

With Clayton Kershaw and Brett Anderson already scheduled to pitch the first two games of a three-game home series against the Colorado Rockies that starts Monday, Mattingly said Alex Wood — not Latos — would pitch Wednesday.

The Dodgers have a day off Thursday, meaning they won’t have to use a fifth starter until Sept 22, whether it’s Latos or Mike Bolsinger.

Dream debut

Ronald Torreyes was in disbelief as he stood on second base in the fifth inning.

Moments earlier, the 23-year-old infielder from Venezuela had doubled down the left-field line in his first major league at-bat.

“I couldn’t believe it, but that was the reality I was living,” Torreyes said in Spanish.

Torreyes, who finished the minor league season with triple-A Oklahoma City, traveled to Arizona with the expectation that he would be training at the Dodgers’ spring-training facility in case one of the infielders on the major league roster went down because of an injury. When his airplane landed, however, he learned the plans had changed.

“When I got to the airport, they told me they had already called me up,” Torreyes.

His pinch-hit appearance Sunday was also unexpected, as he was called on to replace Jose Peraza, who reaggravated a hamstring injury.

Torreyes took a winding road to the major leagues. He signed with the Cincinnati Reds at age 17, but was traded multiple times and played in the farm systems of the Chicago Cubs, Houston Astros and Toronto Blue Jays. The Dodgers purchased his rights from the Blue Jays on June 12.

In 110 games this season at double A and triple A, Torreyes batted .261 with 18 doubles, four home runs and 36 runs batted in.

Extra bases

Yasiel Puig, who is rehabilitating a strained hamstring at the Dodgers’ nearby spring-training complex, showed up at Chase Field. Puig is supposed to return to Los Angeles next week. … The Dodgers traded minor league infielder Darwin Barney to the Blue Jays in exchange for double-A catcher Jack Murphy. Barney was on the Dodgers’ opening-day roster but was removed from the team’s 40-man roster in June to clear a place for Torreyes.

dylan.hernandez@latimes.com

Twitter: @dylanohernandez