1919 29 Red Sox, home park: Fenway Park
1920 54 Yankees, home park: Polo Grounds
1921 59 Yankees, home park: Polo Grounds
1927 60 Yankees, home park: Yankee Stadium
In 1961 the American League expanded by 25%, increasing from 8 to 10 teams. The National did the same in 1962. The schedule increased five percent from 154 games to 162. Five percent of 60 is 3. In a general sense to equal 60 HR in 162 games the total should be 63 HR.
In 1961 the Washington Senators moved to Minneapolis and became the Minnesota Twins and were replaced by a new expansion team called the Washington Senators. The other expansion team was the Los Angeles Angels.
The two new teams were stocked with players drafted from the 8 AL teams. The dilution of talent of the 16 major league teams was about 12%. Weaker pitchers and weaker batters were playing in the AL and NL who would not have been playing in 1960. There's no getting around that.
Did Maris specifically take advantage of the two new expansion teams? It doesn't really matter as all teams were impacted.
Including Cepeda and Mays in the NL, eight players hit at least 40 HR in 1961. All but Killebrew and Mays had career highs in HR in 1961.
Maris hit only three HR against the Orioles but he also had his fewest at bats (AB) against them, so let's look at his HR rate.
Among the HR leaders, only Mantle had a better HR rate than Maris. HR rate for AL teams:
The Senators pitching staff had the second best AL HR rate but the Angels had the worst. Maris had his fewest HR against the Orioles and they allowed the fewest HR. Here are his HR Rates against AL teams.
|Chicago White Sox||13||71||5.46|
|Boston Red Sox||7||65||9.29|
|Kansas City Athletics||5||67||13.40|
|Los Angeles Angels||4||59||14.75|
It's not clear that Maris took particular advantage of the two expansion teams: Senators and Angels. Here is how Maris did by ballpark.
Maris had an overall HR rate of 9.67, so he was only slightly better in Yankee Stadium.
In 1960 Maris had a much better HR Rate on the road, about what he had on the road in 1961. He was on pace to hit about 55 HR in 1960 when he was injured. In the first half of 1960 in 72 games Maris hit 27 HR in 310 AB. In 1960 Maris batted mostly third and fourth. He and Mantle had these PA in those spots:
Mantle was not protecting Maris in 1960 as he did in 1961. In 1960 Yankee manager Casey Stengel moved Maris to number 3 and Mantle to 4 in September and in all seven World Series games Stengel batted Mantle lower in the Yankee batting order than Maris. It was Stengel, not his replacement in 1961 Ralph Houk, who switched them to have Mantle protecting Maris. The pattern was largely in place in early September 1960 and for Yankee games 147 (9/23/1960) though 155 (10/2/1960) it was Maris 3, Mantle 4 in every game. Roger Maris had become a Home Run hitter in 1960.