Prior was slowed this spring because of inflammation in his right elbow and started the season on the disabled list. He'll slide into the vacant fifth starter spot and the team will make a corresponding roster move on Tuesday.

"We feel he's ready. He feels good," Cubs manager Dusty Baker said Monday.

Prior tuned up with 88 pitches for Triple-A Iowa against Albuquerque last Thursday.

"He knows himself better than we do," Baker said. "We know he didn't feel any discomfort or pain."

The Cubs placed Prior on the DL so he could build up more endurance and arm strength after missing one week in Spring Training.

"My endurance feels good," Prior said Monday. "I felt good throwing the other night. Obviously, when you step into the ballgame [Tuesday] the intensity is a little greater. We'll just have to play it by ear. My arm feels good."

Fortunately for Prior, the slate is wiped clean and his stats in Albuquerque don't count. He gave up seven runs on nine hits and one walk over six innings while striking out seven.

"I know what I'm capable of doing," he said. "I'm not worried about how I threw down there."

Substitute second baseman: Neifi Perez started at second base on Monday and went 1-for-3 in Day 1 without Todd Walker, who will be sidelined four-to-six weeks with a sprained left knee.

Baker said he'll start either Perez or Jerry Hairston, depending on matchups. Perez had faced San Diego starter Adam Eaton before and was 6-for-21 against him, while Hairston had never seen the right-hander.

"We'll work it out," Baker said.

The Cubs also called up infielder Mike Fontenot from Triple-A Iowa to take Walker's spot on the roster. Fontenot, acquired from Baltimore in the Sammy Sosa trade, was batting .308 in four games. Another second base prospect, Richard Lewis, was hitting .125 for the Iowa Cubs.

Fontenot was watching The Masters golf tournament in the clubhouse in Albuquerque when he got the news on Sunday.

"I was thrilled," he said. "I started off pretty good and I felt good in the box. I was very glad to get the season started."

He played three games at third base and one at second for the Iowa Cubs. Now, he'll wait and see what Baker has in mind.

"This is real cool," he said of being in the big leagues for the first time. "This is what you play for your whole life."

Fontenot was prepared for the tight quarters of Wrigley's home clubhouse.

"I didn't know what to think -- they were saying how small it was," he said. "This is the first big league clubhouse I've been in. I walked through the one in Camden [Yards] but never really looked. But, hey, this is great."

The Cubs will likely call on Perez and Hairston more than Fontenot.

"I'm just glad we have the guys that we have here, guys like Neifi and Hairston," Baker said. "You've just got to find a way. We'll just do what we have to do and go with what we have."

Walker joins Joe Borowski on the disabled list. Borowski suffered a non-displaced fracture in his right wrist fielding a comebacker on March 21, although he did play catch for a second day on Monday.

The Cubs had to deal with their share of injuries last season.

"When you have a great team and you have a chance to win the World Series, like we did last year and this year, and then you start having injuries all over the place, it's extremely frustrating," Walker said. "With me feeling as good as I did at the plate, it's a big setback.

"We have a great team," Walker said. "They'll put Neifi or Jerry in there and we'll be fine. Personally, I feel I can make a difference in games. If we happen to start losing, that's when it gets tough."

Walker was batting .381 with two doubles and three RBIs in the first six games.

Waiting in line: Hairston expected to see his name in Monday's lineup as Walker's substitute.

"I'd be lying -- I'm not a very good liar. I was a little disappointed," Hairston said. "I'm happy for Neifi Perez. He's a good player, a great guy. I'm happy for him as well."

Hairston said he'll wait his turn.

"I don't make the lineup," he said. "That's not my job. All I do is show up and try to work hard and prepare myself. That's all I try to do."

Hairston, acquired in the Sosa deal, batted .303 in 86 games for Baltimore last year, and has a career .261 average.

"I don't have to prove myself to anybody," Hairston said. "What I've done when I've been healthy in the lineup speaks for itself. There's guys in here who have played against me, guys like Nomar [Garciaparra] and Todd Walker. I just go out when I'm in there and have fun and enjoy the game."

Minor matters: Calvin Murray went 2-for-4 with an RBI in Iowa's 3-2 loss to Albuquerque on Sunday. Left-hander Jimmy Anderson gave up two runs on six hits over 5 1/3 innings. ... Brandon Sing hit two home runs and drove in three runs and Felix Pie had two doubles for Double-A West Tenn in a 9-6 loss to Chattanooga.

On deck: After Prior starts on Tuesday, Kerry Wood will close the series against San Diego on Wednesday. ... Participating Chicago-area Walgreens stores will sell the Cubs' "Believe" bracelets, starting Friday. All proceeds will go to Cubs Care.

Cubs mailbag: Have a question about the Cubs? We'll run a mailbag on Thursday, so e-mail your queries to cubstuff2005@yahoo.com. Please include your first and last name and hometown.