GOODYEAR, Ariz. -- Lefty Sean Marshall will officially open the 2012 season as the Reds' closer, manager Dusty Baker announced after his team's final Spring Training game on Monday.

The move has been anticipated in Reds camp after the club learned that closer Ryan Madson would need season-ending surgery to repair a torn ligament in his elbow. The other option would have been a closer-by-committee set up.

"It's Marshall right now," Baker said after the game, adding he's been impressed with Marshall's spring.

In 10 appearances, Marshall has a 3.27 ERA and has held opposing hitters to just .179 at the plate. Marshall struck out 16 batters in 11 innings this spring, while walking three. He is slated to pitch again Tuesday in the the club's Futures Game at Great American Ballpark.

It will be the first time Marshall has been designated as the closer. In six seasons with the Cubs, he had seven saves while posting a 3.96 ERA. He made 78 appearances last season and notched a 2.26 ERA, the lowest of his career.

"He can throw that breaking ball any time, which is tough to do in Arizona with this light air here," Baker said. "He's basically unfazed by situations and things. He's been around a while and he's a veteran guy that's had good success."

Janish the odd-man out on Reds' roster

GOODYEAR, Ariz. -- The white board in Dusty Baker's office at the Reds' spring training complex contains his entire spring squad in a position-by-position breakdown.

Shortstop Paul Janish's name was not included as the white board was whittled down to 25 names for the first time this spring.

Janish pieced together a very solid Cactus League, batting .300 with a .912 OPS. But with Todd Frazier, Wilson Valdez and Willie Harris making the club, there was no room for the right-handed hitting shortstop on the season-opening roster.

"There's always going to be somebody that had a good camp, and there's always going to be tough decisions," Baker said. "This is why I probably despise the week as much as any week in the whole year for me."

The arrival of rookie Zack Cozart put Janish's future in question. Then, when the Reds acquired Valdez from Philadelphia in January, they had a more versatile candidate than Janish for a utility role.

"It made it tough when we went and got somebody like Valdez that can play short and play different positions and that comes from a winning background," Baker said.

Baker opted to start the season with 14 pitchers and 11 position players, and he did so with Friday's off-day in mind. The club will re-evaluate the pitching staff over the weekend and may decide to add another arm to the mix. If that happens, Baker will have another decision to make about subtracting from his bench.

Baker was adamant about the fluidity of his roster this season, noting there's a "great chance" that Janish will be back with the big league club this season.

"I gave Paul the opportunity last year until Cozart came along, and that's just the nature of this game," Baker said. "It's yours until you nail it down or things don't go as well as you and everybody else hoped it would. And now it's Cozart's to nail down, and if he doesn't nail it down, it could be somebody else's after that."

Arroyo ends Spring Training on high note

GOODYEAR, Ariz. -- With his first regular season start looming on Sunday, Bronson Arroyo had planned to go at about 85 percent Monday.

But he felt so good just before his final Cactus League outing that he changed his mental approach to that of a regular season game situation.

Arroyo's spring officially ended with 6 1/3 innings of one-run ball. He finished with a 1-2 record and a 4.97 ERA in his six starts.

"I was going to dial it back a little bit, but as I was throwing my bullpen, I felt really smooth and nice and easy," Arroyo said after he scattered seven hits and struck out four. "So I cranked it up a little bit more than I thought I would. It still felt comfortable."

Arroyo said he felt a little soreness following his last couple of outings, and that's why he was planning to ease up a bit on Monday. In those outings, he said he felt like he had to labor through innings, while on Monday everything was smooth and flowed well.

"Today was definitely the best I've felt overall -- command, all my pitches being there, body not aching as much," Arroyo said. "That's as good as I could have asked for to be primed for the season."

Arroyo will make his first start of the season against the Marlins on Sunday at Great American Ballpark.