Virginia Gov. Bob McDonnell announced a plan Thursday to allow teachers from the Teach for America program to work in Virginia's schools, let local school systems opt out of certain state requirements and change the way school assessments are presented to parents.

Other proposals include giving a $750,000 grant to the private Virginia Early Childhood Foundation to develop a way to assess whether students are ready for kindergarten and allowing local school systems -- rather than the state -- determine how many librarians, school counselors and other support staff they need.

Because the full text of the legislation is still being developed, Thursday's proposal raised several questions among Northern Virginia union leaders.

Fairfax Education Association President Michael Hairston expressed particular concern with the plans to bring Teach for America -- a nonprofit that trains recent college graduates to be teachers before placing them in struggling schools -- into the commonwealth's campuses.

"Traditionally, that's a program that we haven't been very fond of," he said, pointing out that most program participants teach in a specific school for only two years. "All the studies say that teachers really come into their own after they've been around for a while."

The Teach for America training program currently does not qualify participants to teach in Virginia, explained McDonnell spokesman Jeff Caldwell. The governor's proposal would allow program fellows to be certified in Virginia schools and get placed in schools that are difficult to staff.

Hairston also worried that McDonnell's plan to assess school performance based on grades from A to F, rather than in the current numerical system, will not "show the school in the best possible light."

The governor also has suggested allowing school systems to change students' education requirements based on the areas where students might be lagging, rather than on state requirements.

The move might be beneficial if it allows a local district to eliminate an unnecessary and burdensome requirement, said Fairfax County Federation of Teachers President Steven Greenburg. But he also worried that the flexibility could be misused.

The proposal is the second of three that McDonnell plans to introduce as part of his education reform package for the General Assembly session that begins next week.

The first portion proposed a 2 percent pay raise for Virginia teachers, in exchange for teachers reaching tenure at five years, not three. The package also would redefine incompetence as including "one or more unsatisfactory performance evaluations."