PITTSBURGH — The Roman Catholic Diocese of Pittsburgh is preparing to lay off workers to avoid a $2.3 million deficit for the 2012-13 fiscal year.

A letter to the diocesan staff from the Rev. Ronald Lengwin, the vicar general, said $1 million has already been saved by 15 employees who have retired, resigned or been reassigned. Still, more of the diocese's 180 clergy and lay employees may have to be laid off.

Lengwin wouldn't specify other possible cuts, because they are under review by the diocesan finance council.

"Unfortunately, a significant deficit remains," Lengwin said. Workers won't get annual bonuses and the diocese "will still face the necessity of additional staff reductions," he said.

The diocese is facing financial trouble partly because revenues from parishes has been flat while costs have increased. The diocesan budget for 2011-2012 was $23.2 million, but income for the coming year is projected to be just $21 million.

The six-county diocese has 635,000 parishioners, down from 815,000 in 1993, but the diocese is cutting expenses because it's committed to not running a deficit. The last time that happened was in 1989.

"We tell the parishes that they need to live within their means, and we need to do the same," Lengwin said.

The diocese is funded by a share of the collections from its parishes. The budget is largely for administrative staff, including central church offices and the higher levels of administration for its Catholic schools. But the diocesan budget doesn't include its social service agencies or parishes, which have their own budgets.