You don't win 5 World Series championships in a row by accident. You also don't win them with the entirely same lineup. Sure, rising stars like Berra can start to peak right at the onset and contribute the entire way through, but you also need well established superstars like DiMaggio. Guys at all different parts of their careers, some rising up and others on the back half, contribute to a dynasty. For those on the back half, the team needs to find guys to cover for the talent if the team wants to maintain their status on top. The Yankee Clipper would play in what would be his final season. DiMaggio felt he wasn't able to maintain his exacting elite standards.
The pending departure of DiMaggio would mean that the Yankees would have a massive hole in the heart of their lineup. With this being year 3 of what would be 5 titles in a row, it stands to reason that the Yankees somehow found a Hall of Fame caliber talent to take over for Joe...to the detriment of the rest of the baseball world, they did. 1951 would be a passing of the torch year, where Joe D would step away as the Mick arrived.
The regular season was what was becoming a routine thing for New York; yet another pennant featuring a 98-56 record, 5 games ahead of the 2nd place Cleveland Indians. The World Series that year featured a battle of all time great Managers as Casey Stengel matched wits with Leo Durocher of the New York Giants. It also played host of a head to head between the explosive young stars as Mantle and Willie Mays signaled a new era of baseball in NYC.
The Giants took first blood in the series, and mounted a 2-1 lead when things shifted to the Polo Grounds, but then the Yankees took charge. They weathered a rain delay and an early Giants lead in Game 4 to triumph 6-2, then thumped their way to a 13-1 blowout the take a 3-2 series lead back to Yankee Stadium. Game 6 was tied until the 6th inning, where Hank Bauer hit a bases loaded Triple to give the Yankees a 4-1 advantage. The Giants would rally to make it 4-3, and with 2 outs Hank Bauer would prove the hero again as he made a sliding catch to end the game with the tying run on base and claim the 3rd straight title for the Bronx Bombers.
Berra would claim the 1st of his three MVPs in 1951 behind his team leading 27 Home Runs, 88 RBI and 161 Hits.
DiMaggio battled through injury and seemed to have a mortal season. Unhappy with his level of play, DiMaggio decided to retire rather than play on with diminished ability. Even with his missing seasons from WWII service and skipping his twilight seasons that could add to his career totals, he still went out as a no-brainer for not just the Hall of Fame, but in the conversation for all time greats...but not before he hit one final World Series homer.

Mantle arrived to such hype about him being the next DiMaggio, that he was originally given the next number after DiMaggio's #5. As #6, Mantle struggled and was sent back down to the minors. He returned later that season with a new number that may sound more familiar. 1951 would be Mickey's arrival, but also the beginning of injury problems as he massively injured his knee during Game 2 of the World Series. That knee injury would start off one of baseballs greatest "what if" debates on how much greater Mantle would be in his career without the injuries holding him back.
The rest of the lineup. Rizzuto would join Berra and DiMaggio at the all star game while leading the team with 18 Stolen Bases. Along with Woodling, he'd also add a Home Run to the cause during the World Series.
Bench players. Collins would hit a homer as well in the series against the Giants. You'll notice Cliff Mapes wearing #7, which was available for Mantle upon his return from the minors after the Yankees traded Mapes away in July.
Raschi was the workhorse for the Yankees, throwing 258.1 Innings and also leading with 21 Wins while leading all of baseball with 164 Strikeouts. His efforts earned him a top 10 finish in MVP voting for the 2nd straight year. He closed his year strong with the Win in the clinching Game 6 against the Giants.
Allie Reynolds has a misleading 8IP on his card, which is only because he would sometimes come out of the bullpen for the Yankees. Of his 40 games, 26 were starts and 11 of the remaining games were pitched until the end to give him 17 Wins and 6 Saves. That 8IP is misleading because 16 of those 26 starts had him going all the way for Complete Games, including a baseball leading 7 Shutouts to help him finish 3rd for MVP and not one but two No Hitters (The 1st AL pitcher and 2nd ever to notch multiple no-nos in the same season). He'd continue his pitching prowess when he added another Win in Game 4 of the series in a Complete Game effort.
Lopat rounded out the big 3 in the rotation by tying Raschi with 21 Wins, leading the staff with a 2.91 ERA and was the only pitcher on the team to get an all star nod. He continued his heavy lifting in the World Series with Wins in both Game 2 to tie the series up, and Game 5 to put the Yankees a win away from the title.
No official "Closer" for the pitching staff. The 6 Saves Joe Ostrowski pulled off tied him with Allie Reynolds for the most on the team. Bob Kuzava added 5 of his own, plus the only Save for the Yankees in the World Series as he closed the door in Game 6 to clinch the title.
The AL Rookie of the Year for 1951 went to a Yankee, but not Mantle. Gil McDougald won the award with his team high .306 Batting Average and 9th overall finish for the MVP. He didn't slow down in the World Series, either, as he made history in Game 5, becoming the 1st rookie to hit a Grand Slam; a 3rd inning blast that broke a 1-1 tie in an eventual 13-1 thrashing.