Javier Lopez, in his second stint with the Red Sox, served as an at-times vital cog in the team. He spent parts of four years with the Sox, from 2006-09, and in 172 appearances with the club, he had a 3.30 ERA.

But the end was rough. In 2009, he appeared in 14 games for the Sox, and allowed 20 hits and 12 earned runs in 11 2/3 innings. His 9.26 ERA — and the ascent of Daniel Bard in the minors — resulted in the left-hander being designated for assignment to clear a spot on the big league roster for Bard in early May.

“I really don’t think I threw the ball all that bad,” Lopez told Alden Gonzalez in a terrific feature on the left-hander on MLB.com. “But when I decided to get hit around pretty bad, I made sure I did a good job of it. I made sure I got hit around.”

He did a good enough job of it that the Sox could not be faulted for releasing him at the end of last season. But, much to his surprise, one year later Lopez has emerged as an enormous contributor for the Giants, who now lead the World Series, 2-0.

After San Francisco acquired him from the Pirates at the trade deadline, the 33-year-old had a 1.42 ERA in the regular season. In the postseason, he has delivered many crucial outs for the Giants, permitting just one hit, one walk and one run in 5 2/3 innings (1.59 ERA) while striking out six. He has been called upon to neutralize the best left-handed hitters of playoff opponents — Jason Heyward of the Braves, Chase Utley and Ryan Howard of the Phillies, Josh Hamilton of the Rangers — and he has succeeded.

“If you told me in May or June that I’d be here, in this spot, I’d tell you you’re lying to my face,” Lopez said in the MLB.com story. “It’s a dream. These are the spots that you try to play all your life for.”