LA Dodgers slugger Manny Ramirez has been suspended for 50 games by the MLB for the use of a performance-enhancing substance.

No details were provided by the league on the nature of the substance, but Ramirez quickly issued a statement in which he said it was not a steroid, and had been prescribed to him by a physician.

"Recently, I saw a physician for a personal health issue," said the statement, which was issued through the MLB Players' Association.

"He gave me a medication, not a steroid, which he thought it was okay to give me.

"Unfortunately, the medication was banned under our drug policy. Under the policy that mistake is now my responsibility.

"I have been advised not to say anything more for now. I do want to say one other thing; I've taken and passed about 15 drugs tests over the past five seasons."

Ramirez went on to apologise to the Dodgers and their ownership.

He continued: "I want to apologise to Mr McCourt, Mrs McCourt, (manager Joe) Torre, my team-mates, the Dodger organisation, and to the Dodger fans.

"LA is a special place to me and I know everybody is disappointed. So am I. I am sorry about this whole situation."

The Players Association confirmed that Ramirez will not appeal the ban.

Ramirez will begin his suspension immediately, and becomes by far the most high-profile player to have been caught by MLB's oft-criticised drugs policy which, while significantly strengthened in recent years, does not go as far as other leagues around the world.

Ramirez, 36, is in his first full season with the Dodgers, and is batting .348 with six home runs and 20 RBI through the first 27 games of the year.

The 12-time All-Star signed a two-year, US dollars 45 million deal with the Dodgers earlier this year, after initially rejecting it and testing the market.

He joined the Dodgers in a trade from the Boston Red Sox last summer, and was credited with lifting a young team into the play-offs.

With the ban coming into effect with tonight's game against the Washington Nationals, Ramirez will not be eligible to return until July 3.

News of the suspension for Ramirez comes just as baseball was preparing for the return to action of Alex Rodriguez, the New York Yankees third baseman who spent much of spring training acknowledging and then facing questions over his own use of performance-enhancing substances earlier in his career.

Rodriguez was the subject of a new book, released earlier this month after being serialised in February, claiming he had used steroids over several years. Rodriguez acknowleged using them between 2001 and 2003, while with the Texas Rangers.

He is yet to play this season due to a hip injury, but could return as early as tomorrow.

Like Rodriguez, Ramirez could now face questions over how the use of performance-enhancing substances will affect his Hall-of-Fame credentials.

So far, voters have shown no inclination to elect those who have acknowledged or who are merely suspected of having used such substances during their careers.

MLB introduced new, harsher drug policies in 2006.

A first positive test results in a 50-game suspension, a second positive test draws a 100-game suspension and a third positive test a life-time ban.

All suspensions are without pay, meaning Ramirez will lose almost a third of the USD 25 million he was due to be paid this season.