<PAGE>


EXHIBIT 10.9 - STOCK OPTION AGREEMENT BETWEEN ALTERNATIVE RESOURCES CORPORATION
AND STEVEN PURCELL


NON-QUALIFIED STOCK OPTION


     THIS NON-QUALIFIED STOCK OPTION, granted this 3rd day of August, 1998, by
Alternative Resources Corporation, a Delaware Corporation (the "Company"), to
Steven Purcell (the "Optionee").


                                   WITNESSETH:

     WHEREAS, the Board of Directors of the Company is of the opinion that the
interests of the Company and its subsidiaries will be advanced by encouraging
and enabling those employees of the Company and its subsidiaries, upon whose
judgment, initiative and efforts the Company is largely dependent for the
successful conduct of the business of the Company and its subsidiaries, to
acquire or increase their proprietary interest in the Company, thus providing
them with a more direct stake in its welfare and assuring a closer
identification of their interests with those of the Company; and

     WHEREAS, the Board believes that the acquisition of such an interest in the
Company will stimulate such employees and strengthen their desire to remain with
the Company or one of its subsidiaries;

     NOW, THEREFORE, in consideration of the premises and of the services to be
performed by the Optionee, under paragraph 2 hereunder, the Company hereby
grants this non-qualified stock option to the Optionee on the terms hereinafter
expressed.

     1. OPTION GRANT. The Company hereby grants to the Optionee an option to
purchase a total of two hundred thousand (200,000) shares of Common Stock of the
Company at an option exercise price of $13.81 per share, being not less than
100% of the Fair Market Value of a share of Common Stock on the date hereof.
This option is NOT intended to qualify as an "incentive stock option" within the
meaning of Section 422 of the Internal Revenue Code of 1986, as amended (the
"Code").

     2. TIME OF EXERCISE. This option may be exercised (in the manner provided
in paragraph 3 hereof) in whole or in part, and from time to time after the date
hereof, subject to the following limitations:

     (a) This option may not be exercised during the first six (6) months from
the date hereof. Thereafter, it may be exercised to a maximum cumulative extent
of 2.38% of the total shares covered by this option on and after February 3,
1999, and as to an additional 2.38% of the total shares covered by this option
on and after the last day of each calendar month thereafter through and
including July 3, 2002, after which date this option, to the extent not
previously exercised, may be exercised in full. For practical reasons, the
Company may allow options to be exercised only at the end of each calendar
quarter.


     (b)  This option may NOT be exercised after the earliest to occur of any of
          the following:

     (i)  after the termination of the Optionee's employment with the Company or
          one of its subsidiaries for "cause" (which shall have the same meaning
          as set forth in any employment agreement between the Optionee and the
          Company);or

     (ii) more than thirty (30) days after the termination of the Optionee's
          employment with the Company or one of its subsidiaries for any reason
          other than a termination by the Company for Cause or by reason of the
          Optionee's permanent disability or death (and then only to the extent
          the Optionee is in compliance with any covenant not to compete with
          the Company as set forth in any employment agreement between the
          Optionee and the Company and only to the extent the Optionee could
          have exercised this option on the date of termination);

    (iii) more than six (6) months after the termination of the Optionee's
          employment with the Company or one of its subsidiaries by reason of
          the Optionee's permanent disability (within the meaning of Section
          22(e)(3) of the Code) or death (and then only to the extent the
          Optionee could have exercised this option on the date of termination
          or death); or

<PAGE>

     (iv) more than 10 years from the date hereof.

     3. METHOD OF EXERCISE. This option may be exercised only by notice in
writing delivered to the Treasurer of the Company and accompanied by:

     (a) The full purchase price of the shares purchased hereunder payable by a
certified or cashier's check payable to the order of the Company; and

     (b) Such other documents or representations (including without limitation
representations as to the intention of the Optionee, or the purchaser under
paragraph 4 below, to acquire the shares for investment) as the Company may
reasonably request in order to comply with securities, tax or other laws then
applicable to the exercise of the option.

     4. NON-TRANSFERABILITY; DEATH. This option is not transferable by the
Optionee otherwise than by will or the laws of descent and distribution and is
exercisable during the Optionee's lifetime only by him. If the Optionee dies
while employed by the Company or one of its subsidiaries, this option may be
exercised during the period described in paragraph 2(b)(iii) (but not more than
10 years from the date hereof) by his estate or the person to whom the option
passes by will or the laws of descent and distribution, but only to the extent
that the Optionee could have exercised this option on the date of his death.

     5. CANCELLATION. In the event that the Optionee accepts a position within
the Company with less responsibility than the position held at the date of this
grant (as determined by the Company), and for which this grant applies as
detailed in the transmittal letter accompanying this grant, the Company shall
have the right to terminate any non-vested options under this grant, as of the
date the new position is assumed.

     6. REGISTRATION. The Company shall not be required to issue or deliver any
certificate for its Common Stock purchased upon the exercise of this option
prior to the admission of such shares to listing on any stock exchange on which
shares may at that time be listed. In the event of the exercise of this option
with respect to any shares subject hereto, the Company shall make prompt
application for such listing. If at any time during the option period the
Company shall be advised by its counsel that shares deliverable upon exercise of
the option are required to be registered under the Federal Securities Act of
1933, as amended, or that delivery of the shares must be accompanied or preceded
by a prospectus meeting the requirements of the Act, the Company will use its
best efforts to effect such registration or provide such prospectus not later
than a reasonable time following each exercise of this option, but delivery of
shares by the Company may be deferred until registration is effected or a
prospectus is made available. The Optionee shall have no interest in shares
covered by this option until certificates for the shares are issued.

     7. SUBJECT TO PLAN. This option is subject to all of the terms and
conditions set forth in the Company's Incentive Stock Option Plan (the "Plan"),
as adopted on April 29, 1994 and amended on April 26, 1996 and April 29, 1997.
Any capitalized terms not defined herein shall be subject to the definitions set
forth in the Plan.

     IN WITNESS WHEREOF, the Company has caused this non-qualified stock option
to be executed on the date first above written.

ACCEPTED                              Alternative Resources Corporation

/s/ Steven Purcell                    By: /s/ Bradley K. Lamers
------------------                        ---------------------
Optionee                              Its:  VICE PRESIDENT