Faced with a shrinking roster of active police officers and upcoming changes to pension law this summer that may boost the number of officers heading into retirement, the Minneapolis Police Department is on track this year to become the smallest it's been in decades.

Some 812 officers cover the city's five precincts as of this week, but retirements and the expectation that new officers won't be ready to patrol until next year may push the department to something close to 775 sworn members, the smallest roster the department's had in 20 to 30 years, according to police union president John Delmonico.

"If the past is the predictor of the future, we're going to be short cops," he said.

The city has a working goal of 850 police officers, and this year's $146.2 million police budget supplies enough money to get there, according to Mayor Betsy Hodges.

It takes time to hire new officers, however, and although a class of 11 recruits will graduate from the police academy on Feb. 20, the next two groups of officers expected from the academy won't be finished with their academy work and field training until 2015.

A cadet class of up to 32 officers who have no former law enforcement experience will finish the academy and be ready to begin field training around Labor Day. A second class of undetermined size opens to people who already have their Peace Officers Standards and Training license will start in October.

The academy typically lasts 14 to 16 weeks. The field training that comes afterward can take months: the last group of fresh recruits from the academy included 20 people who graduated July 30, and they're still in field training.

Hodges, the former City Council member who was on the public safety committee, said conversations about the size of the department have been ongoing for several years. She said that she met with Delmonico just last week and that the department's size was among the issues discussed.

"The first thing that I can tell you is that Minneapolis is a very safe city," she said, pointing to the decadeslong drop in the city's crime rate. Violent crime has inched up in the last couple of years, but Hodges said the long-term trends were more significant.

Lucrative to retire early

Adding to concern about retirements this year is a change to pension rules set to take effect on June 1. Officers who want to retire early will see their pensions shrink if they don't do it by June 1. About 10 percent of the state's 10,500 peace officers could be eligible to retire early, and departments statewide have braced for a wave of early retirements.

In Minneapolis, about 166 officers are eligible to retire now. Delmonico said state pension officials told him to prepare for a 10 percent to 20 percent boost in the number of officers retiring this year due to the pension changes. The result could be three to six more officers than the average of 30 who retire each year, he said.

Hodges said not knowing exactly how many retirements are likely this year makes it hard to know exactly how many people to hire.

"We've been preparing for this for a long time," she said. "The overarching message that I want to leave you with is that this is a conversation the city has been having for years."

2 cops per 1,000 people

The department peaked at 916 officers in 2008, but the numbers started dropping that year as the city dealt with the recession and a hiring freeze. Former Chief Tim Dolan appeared before the City Council in 2012 to warn that an aging Police Department might see more retirements start to pick up. At the time, two-thirds of the department was 40 or older.

On a per-capita basis, Minneapolis now has about two officers per 1,000 residents. That's a number more typical of cities in the western part of the country than in the Midwest and South or on the East Coast, according to a Michigan State University study that used FBI data from 2011.

At two officers per 1,000 people, for example, Minneapolis is below Milwaukee (3.4), but slightly above Las Vegas (1.8).

The study examined police staffing levels and determined that many departments reported not knowing exactly how many officers they needed; it concluded that appropriate staffing levels can vary widely from city to city.

Matt McKinney • 612-217-1747