...If not for Mr. October himself, Reggie Jackson. The great Mariano Rivera's incredible career is currently winding down, the final innings of a nearly two-decade run that will land him in Cooperstown as a first ballot Hall of Famer in 2019. One can easily envision a day next summer when his number 42 is forever retired by the Yankees with appropriate pomp and ceremony. Rivera is, of course, the last Major League Baseball player to wear Jackie Robinson's 42, which was retired by MLB on April 15, 1997. Rivera has, in his own words, "carried the legacy of Mr. Jackie for all these years, and I tried to do my best to wear No. 42 and do it with class and honor. Being the last player for us to wear No. 42 is a privilege.” But he almost never got the chance to wear that number because of Reggie Jackson. Jackson was signed by the Yankees to a then-whopping five-year $2.96 million contract on November 29, 1976. The team held a press conference to announce the signing and Jackson was presented with his first set of pinstripes—featuring uniform number 42. The upshot is that Reggie's number 9 that he had worn in Oakland and Baltimore was already being worn by third baseman Graig Nettles—hence the need for a new number. Speculation has centered around manager Billy Martin wanting 42 for his pitching coach (and long-time drinking buddy) Art Fowler, but Fowler didn't join the Yankees until the middle of August of that year—Fowler did take number 42 when did get there. Whatever his reason for not taking the then-available 42, Jackson chose 20 as his number in honor of Frank Robinson. He wore 20 for a very short while in Spring Training, then switched to 44 (in tribute to the just-retired home run king, Hank Aaron.) Jackson's number 44 was retired by the Yankees on August 14, 1993. Imagine if he would have gone on to wear the 42 that was presented to him at his introductory press conference? Mariano Rivera made his Major League debut less than two years later; he then would have been wearing something other than the number 42 with which he is so closely associated. In an odd way, Rivera's 42 is connected to four Hall of Famers—Jackie Robinson, Reggie Jackson, Frank Robinson, and Hank Aaron. He will be joining them in Cooperstown in 2019.