There were a lot of doubts about Alex Rodriguez going into 2015; he had not played in over a year due to a suspension and was coming off a disappointing 2013 in which he played just 44 games, batted .244 and hit seven homers. At age 39, many expected that A-Rod would be lost at the plate and leave the Yankees in a terrible spot due to his contract. But Rodriguez silenced the critics by batting .250 (.286 through July) and launching 33 homers last season. Now it remains to be seen if he can build on that as he prepares to turn 40 on July 27.

Of course, Rodriguez is not the first slugger to play into his forties. Barry Bonds, whom A-Rod is chasing on the all-time home run list, played all the way until he was 42. Bonds suited up for just 14 games at age 40 due to multiple injuries, and when he came back at 41 he was far from his usual self. A lifetime .298 hitter, Bonds struggled to break .270, though he did hit 26 home runs. Bonds would hit 28 dingers the following year and eclipse Hank Aaron’s all-time record, ending his career on a high note.

Speaking of Aaron, “Hammerin’ Hank” played until he was 42 as well, but his last great season came at 39. At 40, Aaron saw his home run total dip from 40 to 20, and his average sank from .301 to .268. His regression continued over the next two seasons until Aaron decided to call it quits.

Even the mighty Babe Ruth struggled late in his career. At 39, Ruth had his worst year as a Yankee (though his .288 average and 22 homers weren’t too shabby) and it was becoming clear that his ability was eroding. Due to Ruth’s desire to become a manager, he forced his way to the Boston Braves via trade. Ruth, whom A-Rod could pass on the all-time home run list with a 28-homer season this year, struggled mightily at age 40, batting .181 with just six homers. By the end of May, Ruth had had enough.

But there are reasons to be cautiously optimistic about Rodriguez in 2016. The legendary Dave Winfield had a career renaissance at age 40 with the Blue Jays, as he batted .290 with 26 homers. Winfield continued to be productive at 41 with the Twins, hitting .271 with another 21 four-baggers.

Chipper Jones was showing signs of wear by the time he was 37 but he continued to be effective past his 40th birthday, hitting anywhere between .264 and .287 in those four seasons, with 60 total homers for the then playoff-contending Braves.

Those looking for more ageless sluggers don’t have to check the history books either. Red Sox DH David Ortiz turned 40 in November, and he is coming off a fantastic year in which he hit 37 home runs, his highest total in nearly a decade.

Father Time may be undefeated, but it’s possible that A-Rod can stay in the ring with the champ for a few more rounds.