"We didn't know what to do with him this spring," manager Terry Francona said. "We knew he would be on the team and we knew he would have a significant role. We just weren't sure what that would be."
The Sox figured out that part of the puzzle pretty quickly.
On Opening Day, Schilling started and Boston built a comfortable lead. Papelbon pitched a perfect eighth inning and closer Keith Foulke, coming back from an injury-plagued 2005 season, allowed a run on two hits in the ninth to complete a 7-3 victory over Texas.
Two days later, Beckett worked seven innings. Mike Timlin pitched the eighth, and this time Francona changed tactics. He turned the ninth over to Papelbon, who struck out two hitters to close out a 2-1 victory. It was his first save, but not his last. Within a week, Papelbon added back-to-back saves at Baltimore and the Red Sox had themselves a closer.
"He assumed responsibility and ran with it," Francona said. "He's been terrific."
He had 10 saves in April, setting a Major League record for rookie saves in the first month of the season. With no runs allowed in 13 appearances, Papelbon earned Rookie of the Month honors.
"It's pretty cool," he said. "I'm excited and proud to get that honor."
By the end of May, Papelbon was still perfect, converting all 20 of his save opportunities.
He started the season with 15 1/3 scoreless innings that followed a string of five shutout innings and 10 scoreless outings in his last 11 appearances in 2005. Through the first week in June, he carried an 0.31 ERA, best in the Major Leagues. The only hiccup came May 3 against Toronto when he allowed the winning run to score in the ninth inning. It was the only run he allowed in his first 28 appearances.
The 20 saves gave Papelbon a Major League Baseball record for consecutive save conversions starting a season. Only 18 other rookies since 1960 have had 20 saves in a season, and Papelbon has over three months to add to his total.
The consecutive conversion streak finally came to an end last Friday night against Texas when he allowed an inherited runner to score in the top of the eighth inning. His first blown save was forgotten, however, by the time the Red Sox scored in the bottom of the inning and Papelbon struck out the side in the top of the ninth for his first win of the season.
He enters Boston's road trip this week with a 0.30 ERA and 31 strikeouts over 30 1/3 innings. He is tied with the Cardinals' Jason Isringhausen for the Major League lead with 20 saves. Opposing batters have managed just a .144 average against him.
"I understand that eventually there are going to be days when I may not close the door," Papelbon said. "I get a lot of satisfaction out of closing. Right now, I'm just going out there to do my job and have fun with it."
At 6-foot-4 and 230 pounds, Papelbon is an imposing figure on the mound. He was a fourth-round pick in the 2003 draft, the 204th player selected after pitching mostly in relief at Mississippi State, coming out of the bullpen 61 times in three seasons.
The Red Sox used him as a starter at Class A Sarasota, where he was 12-7 with a 2.64 ERA in 2004 and then 5-2 in 14 starts at Portland last year before moving up to Pawtucket. It was there that Schilling, on a rehab assignment, introduced him to another pitch -- the splitter.
The new weapon took Papelbon to another level.
"Every outing builds confidence," the pitcher said. "You try to learn as much as you can and use it as experience for the next time out. I just want to go out and attack hitters, not give them a chance to think their way through an at-bat."
So far, so good.