SURPRISE, Ariz. -- Steve Clevenger was behind the plate on Wednesday, and he and Welington Castillo appear to be the two finalists for the Cubs' backup catcher's job.

"It's going to be a tough call for that at the end of spring," Cubs manager Dale Sveum said Wednesday. "They're both doing a great job, they both have things they can contribute. It's one of those things -- who knows what will happen at the end? They've both been working as hard as anybody in camp. They're receiving tremendous, calling games, both can swing the bat a little bit. It'll be an interesting call at the end of this month."

Jason Jaramillo was in camp as a non-roster invitee, but has been unable to play because of soreness in his quadriceps.

"That window is closing, especially with these other two guys doing a good job," Sveum said of Jaramillo's chances. "He needs to get on the field to show us what he can do."

Jaramillo is the only backup catcher candidate with any extended Major League experience, having played in 119 games over three seasons with the Pirates.

Marmol pleased with his mechanics, throwing

SURPRISE, Ariz. -- Carlos Marmol had a quick outing on Sunday in the Cubs' Cactus League opener, striking out one of the three batters he faced. He threw mostly fastballs with a couple of sliders mixed in.

"I feel very good with my mechanics now and how I'm throwing the ball," Marmol said Wednesday. "I just want to go out there and be myself."

Last spring, the Cubs' closer totaled nine innings in Cactus League games, and got off to a good start with seven saves in his first nine chances. He posted a 1.98 ERA in the first month. In 2010, Marmol pitched in 12 spring games, totaling 12 1/3 innings. More work may be good to help him get a feel for his trademark pitch.

"My slider, I know is going to be there," he said. "Now is the time to work on my fastball. I know it's going to be tough, but I'm going to hang in there."

Extra bases

• Paul Maholm threw a bullpen session on Wednesday and will do that again Friday before he gets a start in his first Cactus League game. The left-hander was slowed this spring because of the flu. He threw a simulated game Monday.

"Everything's good," Maholm said.

Looking ahead to the Cubs' upcoming games, Chris Volstad will start Thursday against the Mariners followed on Friday by Travis Wood against the White Sox. Randy Wells and Rodrigo Lopez also are scheduled to pitch Friday. On Saturday, Ryan Dempster will make his second spring start against the Brewers, and Matt Garza is slated to go Sunday against the Dodgers.

Cubs manager Dale Sveum said he'll name the Opening Day starter within the next two weeks. Whoever it is will pitch against both the Nationals and Brewers in the Cubs' first two series.

"It's that big prestigious thing," Sveum said of Opening Day. "But they'll both pitch against the teams we want them to pitch."

• Third baseman Ian Stewart was scratched from Wednesday's lineup, but there was nothing wrong. Sveum admitted he goofed. The plan is for Stewart to play every other day for the first 10 days of camp, and he started at third on Tuesday. He'll be back at third on Thursday. The Cubs also don't want to overdo things with Stewart, who is coming back from a wrist injury.

• Sveum will try to get to the Cubs' Minor League camp before Spring Training ends.

"I think it's good for the manager to go down and talk to the Minor Leaguers himself," he said.

• The first round of roster cuts could come Friday or Saturday, Sveum said. The Cubs do have a stretch of four split-squad games in a six-day span, starting March 15.