"Not good," Hernandez said, wincing. "Bad."

Hernandez was placed on the 15-day disabled list Wednesday after an MRI revealed a bulging disc in his lower back. The Mets activated Kaz Matsui from his Major League rehabilitation assignment and plan to use him at second base Thursday at San Diego.

"We've got to get [Matsui] going," Mets manager Willie Randolph said. "He's been swinging the bat pretty well and we'll get him right in there."

In Spring Training, Hernandez seized an opportunity created when Matsui, the Mets' incumbent second baseman, went down with a sprained right knee.

Now, 14 games into the regular season, Matsui will be able to return the favor.

Matsui had played five games in the Minor Leagues and had good reports, going 3-for-11 with a RBI for the Triple-A Norfolk Tides of the International League. He was 2-for-7 in two games at Class A St. Lucie in the Florida State League.

"I'm not sure what kind of timing [Matsui] has going," Randolph said. "It's a different level. I think he's ready to go."

A 23-year-old rookie, Hernandez was injured Tuesday while fielding a ball during batting practice. He said the spasms allowed him to sleep very little Tuesday night, waking the infielder up with every toss and turn.

Walking deliberately through the clubhouse and in obvious discomfort, Hernandez acknowledged that, historically, he has not been a quick healer. He will stay in New York while the Mets travel to the West Coast and can walk or ride a stationary bicycle, but is unable to perform any baseball exercises until further cleared.

"He has a bulging disc, so who knows?" Randolph said. "It's the first time he's ever had it. There's no way you can put a timetable on it."

Not yet: Cliff Floyd (strained right rib cage) and Carlos Beltran (strained right hamstring) were held out of the lineup again on Wednesday.

Beltran, who originally felt the strain in the third inning Saturday against Milwaukee, appears to be further along in his progress than Floyd. Randolph said he considered using Beltran as a late-inning pinch-hitter against the Braves' Tim Hudson.

"It feels better," Beltran said. "The tightness is still there, but the pain is out."

Beltran said he ran the bases and simulated taking fly balls before Wednesday's game, with no ill effects.

"If it feels like this [Thursday], I'll play," Beltran said.

Floyd, who was hurt scoring from second base against the Braves on Monday night, said he came to the stadium and performed all the usual rehab processes -- icing, stretching, and heat therapy -- though he was unable to take batting practice.

He said he felt better, but cautioned, "Feeling good and going out there and playing are different stories."

Mr. Cleanup: Without Beltran and Floyd filling out the top of the order, David Wright started Wednesday's game against Atlanta as the Mets' No. 4 hitter, batting cleanup for the fourth time this year.

The 23-year-old batted in the four-hole just three times all last season, but insisted there was no special aura or allure to filling the spot.

"It really is, in my opinion, truly overrated," Wright said. "After you get the first time through [the order], who knows where you're going to hit? I think it's overhyped."

Wright said he checks the lineup daily and looks to see who precedes him in the order, his way of remembering when it's time to grab a bat. Other than that, Wright claims the lineup means very little to him.

"It's never, 'Man, I'm hitting fourth, I've got to do something different,'" Wright said. "That's not the way I work. I take the same philosophy whether I'm hitting second, seventh or fifth. It doesn't matter to me. It doesn't make me any more hyped up."

Wright said that a prototypical cleanup hitter hits lots of home runs and strikes out a lot. He believes the Mets don't have one of those anyway, instead collecting a selection of No. 3 and No. 5 hitters.

"I guess I'm just different," Wright said. "To me, it's the same."

For the record, Wright entered Wednesday's game batting 6-for-21 (.285) with no home runs and no RBIs as a No. 4 batter, according to the Elias Sports Bureau.

Checking in: Mike Pelfrey, the Mets' first-round selection in the 2005 First-Year Player Draft, missed his last start for Class A St. Lucie of the Florida State League with a sprained ankle.

Pelfrey, who has made two starts for St. Lucie and has not allowed an earned run over 11 innings, is expected to pitch Wednesday night at Daytona. He is 1-0 with 13 strikeouts and one walk.

This date in Mets history -- April 20: The great Warren Spahn made his second start for a team other than the Braves and gained his first victory as a Met, beating the Dodgers in Los Angeles on this date in 1965. Spahnie, three days shy of his 44th birtrhday, pitched a complete game in the Mets' 3-2 victory, allowing two runs, one earned, in the ninth.

Two years later, another future Hall of Fame pitcher earned his first big-league victory. Tom Seaver pitched 7 1/3 innings in the Mets' 6-1 victory against the Cubs at Shea. Seaver hadn't been involved in the decision in his first start.

On this date in 1986, Sid Fernandez and Roger McDowell, a combination manager Davey Johnson liked -- a left-handed fly ball starter followed by a right-handed ground-ball reliever -- combined to limit the Phillies to two singles in the Mets' 8-0 victory at Shea.

Coming up: Steve Trachsel will face Padres ace Jake Peavy in the opener of a four-game set at PETCO Park on Thursday night at 10:05 p.m. ET