Mayweather's stamina and an ability to adjust in the midst of fights has long been celebrated, but the Alvarez fight will mark the first time he's fought twice in a calendar year since 2007 and the shortest turnaround between bouts -- four months, 10 days -- since he fought Diego Corrales and Carlos Hernandez within four months and six days in 2001.
His trainer and father, Floyd Mayweather Sr., claims the faster return to the ring will be a benefit.
"He'll definitely be sharper because of it," he said. "If you get up and walk down the block one day, then you'll go back the next day and walk a little father. Eventually, you'll start jogging, and then all of a sudden you're running a long distance. It's no different with my son. Being in the ring more often will guarantee he stays sharp."
Oddsmakers have installed Mayweather as a comfortable, albeit not prohibitive favorite. It would take a $280 wager on him to recoup $100 at sports.bovada.lv, while a $100 outlay on Alvarez would return $220 in the event of an upset.
WBA/WBC super welterweight titles - Las Vegas, Nev.
Floyd Mayweather Jr. (WBA champion) vs. Saul Alvarez (WBC champion)
Mayweather (44-0, 26 KO): First title defense; Twenty-second title fight in five divisions (21-0)
Alvarez (42-0-1, 30 KO): Seventh title defense; Third fight in Las Vegas (2-0)
Prediction: "Alvarez is a younger, bigger and stronger edition of the guy who's been groomed to defeat Mayweather for years, but has always failed. The result doesn't change here." Mayweather in 10
Lyle Fitzsimmons is a veteran sports columnist who's written professionally since 1988 and covered boxing since 1995. His work is published in print and posted online for clients in North America and Europe. Reach him at firstname.lastname@example.org or follow him on Twitter: @fitzbitz.