Also expected to participate are David Wright of the New York Mets, Jermaine Dye of the Chicago White Sox, Toronto's Troy Glaus and Carlos Lee of Milwaukee, with two other spots for the July 10 competition at PNC Park in Pittsburgh to be determined.
The field for the Derby historically fluctuates in the days leading up to the event, and with a week to go before the All-Star break, nagging injuries could jumble this field. But the pool of sluggers for the competition is deep, with no fewer than 23 of the top 36 home run hitters in the Major Leagues -- 24 counting AL Final Vote candidate Travis Hafner of Cleveland -- among the possible entrants.
Howard, the 2005 National League Rookie of the Year, has hit 28 home runs and is expected to be among the favorites in what would be his first Derby.
"I look at it the same way a basketball player would look at taking part in the slam dunk contest," Howard said. "It would be cool to take part in that."
Ortiz, who competed in the Derby last season and advanced to the second round, said he is looking forward to another shot.
"I'm going to do it," Ortiz said. "I wasn't going to, but I will."
When asked why he changed his mind, Ortiz replied: "It's a secret."
Glaus said he would accept if he's asked to participate, as did Mets third baseman Wright.
"Sure," Glaus said. "It's part of the whole All-Star experience. We'll see what happens. If they ask me, then it'll be fun to do it. I'll do it, yeah. I did it '01."
Lee indicated he was leaning toward skipping the Derby, citing a sore right hand that he tweaked on a swing in mid-June.
"I don't know now, because of my sore hand," he said. "This time I might have to pass it up."
Hometown favorite Jason Bay, who participated last year, but was eliminated in the first round, indicated he will sit out this time.
"They asked me more than once and I said 'No,'" Bay said Sunday.
That still left numerous other Derby candidates, including Boston's Manny Ramirez; Alex Rodriguez of the Yankees; Vladimir Guerrero of the Angels; Paul Konerko and Dye of the White Sox; Houston's Lance Berkman; Albert Pujols and Scott Rolen of St. Louis; Washington's Alfonso Soriano; Carlos Beltran of the Mets; Atlanta's Andruw Jones; Colorado's Matt Holliday and Philadelphia's Chase Utley.
Jim Thome of the White Sox said he will not be participating.
"No. I'm pretty set on that," Thome said. "I think it's just best for our club not to even go there."
Teammate Konerko was less certain.
"I don't know at this point, I don't know if I'm one of those guys, I'd have to think about it," Konerko said. "If there's just a couple of things going on physically, I may shy away from it."
Tejada won the event two years ago at Houston's Minute Maid Park, beating Berkman in the final round. The Oriole shortstop intends to be a fan this time and won't be competing.
"I'll watch it," Tejada said. "I am going to see it with my kids. I am going to enjoy it with them. No more Home Run Derby for me. I already have one and that's it. The best part is seeing my family. I see my kid, take my kid to the Home Run Derby. That's the best part. I think that's something that makes me real proud to see my family going and enjoy the All-Star Game."
Berkman did not completely close the door on his possible participation.
"It doesn't set up well for me," he said. "To have a chance there, you have to hit left-handed and I don't want to hit left-handed, because I don't want it to mess with my swing. I don't mind hitting right-handed because I don't think I could mess my right-handed swing up. That ballpark is huge in left field, so if I had to hit right-handed, I'd be at a big disadvantage."
If asked, Berkman said he would "definitely think about it."
"If they need somebody to do it, I'm not afraid to embarrass myself and run out there," he said.
Pujols hasn't decided if he will compete.
"I'm going to make up my mind in another four or five days," the St. Louis first baseman said.
Jones said Sunday he definitely won't participate.
"I'm not going to do the Home Run Derby," he said. "You sit out there too long. I experienced it one time already and that was enough for me. You have to wait a while, especially when guys hit a lot of homers in the first round."
Ivan Rodriguez, last year's runner-up, will not try his hand this year.
"I don't think so," he said. "I'll be relaxing. My family's in town and my kids are in town and my girlfriends' kids are in town, so I'll leave early. Right after batting practice, I'm going to go and have fun with them."
Health issues will keep A-Rod out of the Derby.
"I'm all banged up," he said. "They haven't [asked], but if they do, I'm going to say no."
Another possibility is Bobby Abreu of Philadelphia.
Abreu, a Final Vote candidate this year, won the event last year with 41 homers at Comerica Park as he set records for a single round, the championship round and the total for all three rounds of the Derby. Abreu defeated hometown hero Pudge Rodriguez, 11-5, in the final round.
Barry Bonds didn't make the All-Star team and the only Barry who did -- Zito of Oakland -- said he wasn't going to compete in the Derby either.
"No, I don't think I'll do it, mainly because I want it to be fair," deadpanned Zito, who has one career hit. "I want it to be a real competition. I mean, I know Pujols and some other guys are hot, but that right-field porch in Pittsburgh is pretty much cake for a guy with my kind of pop. Albert would have no chance."
Another pitcher would like to throw his bat into the Derby ring. Chicago Cubs pitcher Carlos Zambrano hit his third homer Sunday, the first Cubs pitcher to do so since Fergie Jenkins hit six in 1971.
"It's an honor to represent the Cubs and go there," Zambrano said. "My first year, two years ago, I enjoyed that. My family did also. Hopefully, I can be in the Home Run Derby."
The Century 21 Home Run Derby on ESPN will begin at 8 p.m ET mon Monday, July 10.
Jim Molony is a writer for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.