If your employer provided a Simple IRA and you've left the employer-it is eligible to be moved into a IRA (Direct Rollover) or your employer plan (trustee-to-trustee transfer).  Some employer plans may not accept the money-it really depends on the plan. 

However, first look to see how long the Simple IRA has been established.   The IRS has a two-year rule which penalizes distributions if the account has been established less than two years.  Ouch, it's a 25% penalty.

If a rollover distribution (or transfer) from a SIMPLE IRA does not satisfy the 2-year rule, and is otherwise an early distribution, the additional tax imposed because of the early distribution is increased from 10% to 25% of the amount distributed.

Kiplinger's provides some additional help on Simple IRA Rollovers.