SAN FRANCISO — Federal prosecutors have asked a judge to send former baseball slugger Barry Bonds to prison.

In court documents filed late Thursday, prosecutors objected to a recommendation by a federal probation officer that Bonds get only probation when he’s sentenced for obstruction of justice on Dec. 16.

In the documents, prosecutors asked that Bonds be sentenced to 15 months in prison.

Bonds, 47, was convicted in April of obstructing a grand jury’s sports doping investigation with an evasive answer.

Prosecutors dropped three other counts charging Bonds with making false statements after the jury deadlocked on those charges. They accused Bonds of lying to the grand jury when he denied knowingly taking performance-enhancing drugs and said he allowed only doctors to inject him.