A former Montreal Expos groundskeeper, has said that Major League Baseball's "hit king" Pete Rose regularly used corked bats while playing for the Expos in 1984, according to a recent report from the Montreal Gazette.

"Pete Rose would have his bats corked in the visitors' clubhouse at Olympic Stadium," Joe Jammer, the former groundskeeper, told Danny Gallagher of the Montreal Gazette. "I found out he was corking bats."

Corked bats are not allowed under MLB rules. Using a corked bat in MLB is in violation of Rule 6.03 (a)(5): 

(a) A batter is out for illegal action when:

(5) He uses or attempts to use a bat that, in the umpire's judgment, has been altered or tampered with in such a way to improve the distance factor or cause an unusual reaction on the baseball. This includes bats that are filled, flat-surfaced, nailed, hollowed, grooved or covered with a substance such as paraffin, wax, etc.

One of the perceived advantages of using a corked bat is its change on the bat's weight. A corked bat will cause the bat to be lighter, and in turn, helps players swing the bat more quickly. 

"Pete was too smart to deal with Expos equipment manager John Silverman (to cork his bats in the Expos' clubhouse). So Bryan Greenberg, who worked in the visitors' clubhouse, did it," Jammer told the Gazette. "He took me into a room, a door to the left, and underneath tarps there was this machine.

"...The guy (Greenberg) was saying Rose had been corking his bat for 20 years. The guy said that nobody checks him because he's a singles hitter."

The Montreal Gazette reached out to Greenberg, but he would not discuss any role he might have played in corking Rose's bats. "I really can't answer those questions. I really can't talk about it," Greenberg said.

Rose, whose 4,256 career hits remain an MLB record, played 95 games for the Expos in 1984 before he was traded to the Cincinnati Reds in August. He collected 72 hits while batting .259/.334/.295 for Montreal. Rose retired in 1986 after a 24-year long MLB career. He finished, and still sits, as baseball's all-time hits leader with 4,256 hits.

Rose isn't new to controversy as he was banned from baseball for life in 1989 by MLB commissioner A. Bartlett Giamatti for betting on games as a player and manager. Rose freely admits that he still bets on baseball. 

His reinstatement comes up every so often these days. MLB commissioner Rob Manfred rejected his most recent reinstatement application back in 2015, and Rose recently petitioned for reinstatement after the Astros sign-stealing scandal this past January.