Although he has no proof that Sosa used steroids, he told The Daily Herald of suburban Chicago that it's not hard to figure out.
"C'mon. Of course. There are so many guys who did and it's all going to come out,'' said Wendell.
"Here's a guy [Sosa] who goes from 30 homers to 60 homers every year, and just as fast he's out of baseball. Can't get a job. How's that work?
"Baseball people know this is going to get worse and nobody wants anything to do with the guys who were on the stuff.
"We would sit there in the clubhouse and laugh. How's a guy gain 30 pounds of solid muscle in three months [over the winter]? It's physically impossible without the juice.''
Agent Adam Katz told ESPN that Sosa had no response to his former teammate.
"We all understand this is a white hot issue," Katz said Friday. "People have the right to express themselves, but we have no comment."
Wendell, a Cubs teammate of Sosa's through 1997, is no stranger to the steroids controversy. Two years ago he pointed a finger at Barry Bonds.
"Obviously, he did it," Wendell said at the time of Bonds. "... [I]t's clear just seeing his body."
Bonds, who faces allegations of using performance-enhancing drugs in two books to be released in March and May, responded angrily. Two years later Wendell revisited that episode with the Herald.
"Everybody in Chicago knew what was going on, just like everybody in baseball knows about Bonds," Wendell told the Herald. "The coaches knew. So did the managers and owners. How could they not know?
"Then, Jose Canseco comes out and says it and everybody rips him, and now everything he said was true. A lot more will come out about guys who nobody's talking about yet, too."
Wendell, who is now retired and living with his family in Colorado, has observed the changes caused by tougher testing.
"It was funny to see the guys who were on steroids and then got off them," Wendell told the paper. "You're watching on TV and you see a guy hit a ball and you go, 'That's gone.'
"But the thing is, it used to be gone, and now it's a routine fly ball that the year before the guy hit 10 rows into the bleachers."
Wendell also expects the effects of steroids use manifested in the future.
"You still see Yogi Berra and Phil Rizzuto and Johnny Pesky around, but this era of players is going to be dying early," Wendell told the Herald. "The stats don't lie. The stuff will kill you.
"Who cares if you have unreal numbers? You need that bad to be 'the man' for a few years? Those guys will pay later."