'Stand with Meek Mill' billboard seen over Vine Street Expressway

One billboard has caught the eye of onlookers over the Vine Street Expressway in Philadelphia: it reads "STAND WITH MEEK MILL."

A group of buses wrapped with messages of support for Mill have also been seen parked outside of Philadelphia Police Headquarters.

The ad placements come in the wake of rapper Meek Mill's prison sentence. Mill was sentenced to two to four years in prison last week for violating probation in a nearly decade-old gun and drug case.

MORE: Meek Mill gets 2-4 years in prison for violating probation

The prosecutor called for no prison time, but Common Pleas Judge Genece Brinkley said during the sentencing hearing that the 30-year-old musician had wasted several chances to clean up his act.

His lawyer has said he will appeal the decision.

Hundreds rallied in Philadelphia on Monday evening in support of Mill. Celebrities and athletes also spoke at the gathering, including former 76er Julius Erving, Eagles player Malcolm Jenkins and rapper Rick Ross. Erving called Mill's sentence "excessive" and "cruel."

MORE: Hundreds rally in support of imprisoned rapper Meek Mill

On Tuesday, Pennsylvania Lt. Gov. Mike Stack, who chairs the Board of Pardons, released the following statement regarding Mill's case:

"This week, the Board of Pardons staff received numerous phone calls about the petition seeking action regarding Meek Mill.

As chairman of the board, it would be inappropriate for me to pre-consider or comment on any case that could potentially come before the board.

I have been a strong proponent of criminal justice reform and a supporter of Clean Slate and second-chances legislation now pending in the General Assembly. I have also conducted dozens of Pathways to Pardons seminars across Pennsylvania to explain the system to likely applicants.

However, despite the outstanding and aggressive effort by Board of Pardons staff, which is processing applications at a record rate, a backlog of cases remains before the board. The staff is advising callers to visit the Board of Pardons website for information on how to proceed.

All applicants are treated equally by the board in the order in which they are received.

Under Pennsylvania law, neither the governor nor the lieutenant governor can act on a pardon application without consideration and recommendation by the full board."