Orioles legend Cal Ripken is the only major leaguer to do it.
Albert Pujols came close, but fell short. Fred Lynn and Ichiro Suzuki achieved the impressive feat, but in one year, not successive seasons.
Only the Orioles' Ripken has won a Most Valuable Player award (1983) the season after being named Rookie of the Year. Now, another name could join Ripken's.
Philadelphia Phillies first baseman Ryan Howard, the 2005 National League Rookie of the Year, is making a serious run at Pujols, the New York Mets' Carlos Beltran and the Washington Nationals' Alfonso Soriano for the NL MVP award this season.
The Howard MVP buzz picked up steam in August, about the time the Phillies emerged as a wild-card contender.
"When a team wins a pennant, voters have a tendency to look for the MVP there because they are a top-of-the-line team," Phillies manager Charlie Manuel said. "But if you look at MVP in what he does for a team, then Ryan has to be No. 1. ... Look at Ryan's season right now and it is better than Pujols', and that's what you should go by."
On Thursday, Howard, 26, set the Phillies single-season home run record with his 49th, a towering shot that landed in the upper deck at RFK Stadium. He passed Hall of Famer Mike Schmidt, who hit 48 in 1980.
Howard homered in five of his final six August games to finish the month with 14 homers and 41 RBIs.
"He is a freak of nature," Phillies outfielder David Dellucci said. "There is no one really you can compare him to. He is doing some pretty unbelievable things."
Dellucci said he'd "absolutely, without a doubt" cast a vote for Howard.
"I think it's unfair that he hasn't been getting the publicity he deserves," Dellucci said. "He has helped this team be right in the middle of the wild-card race. Whether we win it or not, he should be the favorite for MVP."
If Howard finishes second in the voting this year, he'd become the first Rookie winner to be an MVP runner-up the next year since Pujols in 2002. Lynn won both AL awards in 1975 and didn't place in the AL MVP voting in 1976. Suzuki won them both in 2001, and finished 17th in the AL MVP voting in 2002.
For the second consecutive year, Nationals manager Frank Robinson was listed as baseball's worst skipper according to an anonymous Sports Illustrated poll of 470 major leaguers. His 17 percent of the vote edged Texas Rangers manager Buck Showalter's 15 percent. Robinson, who turned 71 Thursday and may not be back with the team next year, said he puts no stock into the poll.
"Because I know better," he said. "I know I am not the 30th-best manager in baseball."
Chicago Cubs first baseman Derrek Lee returned last week from the wrist injury that kept him sidelined most of the season and said he didn't think the Cubs' dismal record was directly linked to his absence.
"Even if I was in there, we don't play good baseball, we're not going to win," Lee said.