Trying to decide whether to promote an employee to a management position is a challenge many employers face. But not every employee is a born leader. Pay close attention to all the characteristics of a potential candidate when thinking about offering a promotion, rather than just seeing how long the individual has been with the organization.

For employers thinking about promoting someone into a management position, here are seven warning signs that the person perhaps should not become a boss. Watch out for the following traits:

Related: Why the Best Managers Ask the Most Questions

1. Never asking for help. 

When a high-performing employee never asks for help, it might seem that he or she is extremely talented and self-driven. Although a self-sufficient employee is great to have, this doesn’t necessarily make for a good candidate for a management position. A 2007 study by the Institute for Corporate Productivity found 46 percent of companies surveyed expressed high levels of concern about staffers' delegation skills.

Good bosses effectively delegate tasks and ask for input from their teams. If an employee never inquires of co-workers for help, this might be a sign that the person would not reach out to staff once promoted.

Related: Feel Dumb Asking for Advice? You'll Actually Appear More Competent.

2. Ignoring co-workers' problems.

Employees who go above and beyond on their projects, but don’t lend a helping hand to co-workers in need, might not be manager material.

A study by Gallup found 57 percent of employees who feel ignored by their bosses are not engaged at work. Good bosses are willing to step up to the plate, help employees when needed and do not ignore the challenges they face.

Related: Managers Can Be True Leaders Not Just Taskmasters

3. Blaming others readily.

When something goes terribly wrong with a project, does the employee look away?

Good managers hold themselves accountable when a problem arises and are the first to take action and try to figure things out.

An employee being promoted should demonstrate integrity. Some 20 percent of workers say their boss lacks integrity, according to a survey by TellYourBoss.com.

Related: 9 Ways to Manage Underperforming Employees

4. Lacking passion.

But when looking to promote an employee, pay attention to his or her level of passion. Strong managers can inspire others. According to a study by LeadershipIQ, people who interact with their boss at least six hours a week are 29 percent more inspired than those who only spend one hour a week in such dealings.

5. Overlooking long-term goals.

Many employers have a few rock-star employees who can meet weekly deadlines and exceed expectations. But just because these employees meet short-term goals doesn’t mean they understand how to fit into the overall mission of the company.

Good bosses look at the big picture. They create short-term goals that help their staff come closer to accomplishing the company's overall goal.

Related: How Making Employees Lifelong Learners Can Help Your Company Succeed

6. Not striving for continuous learning.

Although not every employee will know everything about his or her job, taking the initiative to learn as much as possible is important. If an employee doesn’t demonstrate this quality, he or she may not be the best candidate for a promotion.

Pay attention to employees who take action to improve their skills. Strong candidates for management positions are self-starters who make professional development a priority.

7. Being eager to clock out at 5 p.m.

Employees who are in a rush to leave work on time (or even early) each day might not be the best fit for a management position. Although it’s definitely not necessary to work late every night, doing so when needed is crucial.

Good candidates for management positions are willing to put in the time to accomplish goals at work and available to help when needed.

What are some warning signs to pay attention to when weighing whether to promote an employee?

Related: 5 Signs It's Time to Fire a Company Manager