5405. The period within which proceedings may be commenced for the
collection of the benefits provided by Article 2 (commencing with
Section 4600) or Article 3 (commencing with Section 4650), or both,
of Chapter 2 of Part 2 is one year from any of the following:
(a) The date of injury.
(b) The expiration of any period covered by payment under Article
3 (commencing with Section 4650) of Chapter 2 of Part 2.
(c) The last date on which any benefits provided for in Article 2
(commencing with Section 4600) of Chapter 2 of Part 2 were furnished.
The confusing part would be the requirement to file a DWC-1/First Report of Injury with the employer within 30 days of that knowledge.
5400. Except as provided by sections 5402 and 5403, no claim to
recover compensation under this division shall be maintained unless
within thirty days after the occurrence of the injury which is
claimed to have caused the disability or death, there is served upon
the employer notice in writing, signed by the person injured or
someone in his behalf, or in case of the death of the person injured,
by a dependent or someone in the dependent's behalf.
Even if the actual form is not filed with the ER/IC timely, the fact there is knowledge by the ER through any source is generally sufficient to constitute a valid claim, and permits the ER/IC to investigate the claim.
5402. (a) Knowledge of an injury, obtained from any source, on the
part of an employer, his or her managing agent, superintendent,
foreman, or other person in authority, or knowledge of the assertion
of a claim of injury sufficient to afford opportunity to the employer
to make an investigation into the facts, is equivalent to service
under Section 5400.
For CT/Cumulative Trauma injury/illness....
5412. The date of injury in cases of occupational diseases or
cumulative injuries is that date upon which the employee first
suffered disability therefrom and either knew, or in the exercise of
reasonable diligence should have known, that such disability was
caused by his present or prior employment.
The above labor codes are here http://www.leginfo.ca.gov/cgi-bin/wa...ction=retrieve

For a psych/stress claim to be valid, the EE/employee, must have worked for this ER a minimum of 6 months prior to filing the claim.
3208.3 (d) Notwithstanding any other provision of this division, no
compensation shall be paid pursuant to this division for a
psychiatric injury related to a claim against an employer unless the
employee has been employed by that employer for at least six months.
The six months of employment need not be continuous.
If this is a claim for compensation due to a psych/stress injury/illness, there are mandates under the labor code specific to this issue...
(e) Where the claim for compensation is filed after notice of
termination of employment or layoff, including voluntary layoff, and
the claim is for an injury occurring prior to the time of notice of
termination or layoff, no compensation shall be paid unless the
employee demonstrates by a preponderance of the evidence that actual
events of employment were predominant as to all causes combined of
the psychiatric injury and one or more of the following conditions
exist:
(1) Sudden and extraordinary events of employment were the cause
of the injury.
(2) The employer has notice of the psychiatric injury under
Chapter 2 (commencing with Section 5400) prior to the notice of
termination or layoff.
(3) The employee's medical records existing prior to notice of
termination or layoff contain evidence of treatment of the
psychiatric injury.
(4) Upon a finding of sexual or racial harassment by any trier of
fact, whether contractual, administrative, regulatory, or judicial.
(5) Evidence that the date of injury, as specified in Section 5411
or 5412, is subsequent to the date of the notice of termination or
layoff, but prior to the effective date of the termination or layoff.
There are also some SOL mandates here http://www.leginfo.ca.gov/cgi-bin/wa...ction=retrieve.

As you can see, some of the SOL's are dependent upon the injury/illness benefits are being claimed for.

The phone 1-800-736-7401 -- cbg may be referring to is to an Information and Assistance officer at the WCAB.
FAQ's for employER's is here http://www.dir.ca.gov/dwc/employer.htm

IMO... file this claim with your carrier. If you are self insured, hand it off to your TPA/Third Party Adm, or if you are the go to person, it would be important to deny the claim timely, or it could be presumed accepted after 90 days.
IF you are covered under a policy issued by a IC, or SCIF, you should not make the determination on your own, but file the claim with your carrier.