In one effortless inning, Papelbon retired the Reds 1-2-3, starting things off by blowing a fastball by Ken Griffey Jr. for strike three.
The main issue Papelbon had been having was the placement of his arm slot.
"A lot better, my mechanics are getting there," said Papelbon. "One step at a time."
Manager Terry Francona was more specific about the things Papelbon has been working on.
"He had a nice side day the other day," Francona said. "He worked on keeping that arm up a little bit. He had gotten -- where he explained it very uniquely -- where he needs to get on a ferris wheel instead of a carousel, or however he said it. He looked at it on video and went out and had a great side session. It seemed to click."
As for switching from starter to closer in the latter stages of Spring Training, Papelbon issued a reminder of why that should not be a stumbling block of any sort.
"[It's the] same thing I did last Spring Training," Papelbon said. "[I] started all spring and then moved to the 'pen."
Hansen roughed up: Right-hander Craig Hansen, who is likely to start the season in the Minor Leagues, was all over the place during Monday's outing.
Hansen gave up two hits and five earned runs over two-thirds of an inning in which he faced eight batters. He also hit two batters and walked two while striking out two.
"The good part of it is [Hansen] threw the ball, he didn't nurse it up there," Francona said. "The bad side is he was probably doing more throwing than pitching. A lot of balls were getting away. It was frustrating. I'm sure he's frustrated but at least he was letting it go. Again, the ball was flying all over the place."
Decisions loom: The only mystery of the Opening Day roster is the final two pitchers on the 12-man staff. Francona would like to have the decisions made n the next couple of days, if possible.
"As soon as we can," Francona said. "As soon as we know exactly what's going on. I think we owe it to the players, also. But some decisions are a little more difficult than others. We want to make sure everybody is healthy. We don't want to make a decision and then two days later [have somebody get hurt]. ... But we recognize it's going to be difficult. There won't be a pitch-off in Philly."
Down on the farm: No. 5 starter Julian Tavarez continued the process of getting stretched out by pitching a Double-A game on Monday. The righty went five innings and gave up two hits and an unearned run. He walked two and struck out one, while throwing 65 pitches.
Left-hander Jon Lester also continued his throwing program, throwing the equivalent of 1 1/3 innings in a Triple-A game. Lester gave up three hits and three runs, walking two and striking out one.
Position players Wily Mo Pena and Doug Mirabelli also played in the Triple-A game so they could get more at-bats. Mirabelli was 1-for-5 with a double. Pena went 2-for-5 and belted a homer.
Ochoa informed: Though outfielder Alex Ochoa will remain with the Red Sox for these last few days in Florida, he was informed Sunday that he will not make the team.
Ochoa has an out clause in his contract. If he chooses not to exercise it, the Red Sox have cleared a spot for him at Triple-A Pawtucket.
Francona went out of his way to praise Ochoa for the professional way he has gone about his business.
Coco getting his at-bats: For the third straight day, center fielder Coco Crisp was in the lineup. The switch-hitter went 0-for-3 and is hitting .167 this spring.
Crisp was sidelined from March 14-23 with a bruised left shoulder. He has yet to bat right-handed in a game since returning.
"First day up in St. Pete, he looked great," said Francona. "He jumped on a fastball, hit it about 400 feet. Then rifled the ball into right-center. He's to the point where if you send him down to a [Minor League] game to get at-bats, it's not going to do any good. He doesn't want to do it. he's not going to gain anything out of it.
"He's going to get as many at-bats here without running him into the ground as we can. There's a reason Spring Training is the way it is; you play a guy, [then] sit. He's going to play some in a row. We want to get him ready."
Coming up: The Red Sox host the Pirates on Tuesday at 1:05 p.m. ET at City of Palms Park, with knuckleballer Tim Wakefield taking his final turn of the spring. Wakefield will be opposed by former Sox farmhand Tony Armas Jr.
Ian Browne is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.