NONPRECEDENTIAL DISPOSITION
                             To be cited only in accordance with
                                      Fed. R. App. P. 32.1




              United States Court of Appeals
                                   For the Seventh Circuit
                                   Chicago, Illinois 60604

                                  Argued February 29, 2012
                                   Decided April 5, 2012

                                           Before

                             WILLIAM J. BAUER, Circuit Judge

                             ILANA DIAMOND ROVNER, Circuit Judge

                             DIANE P. WOOD, Circuit Judge

No. 11-2750

STANLEY SMITH,                                      Appeal from the United States District
     Plaintiff-Appellant,                           Court for the Northern District of Illinois,
                                                    Eastern Division

       v.                                           No. 11 C 986

UNION PACIFIC RAILROAD                              Robert M. Dow, Jr.
COMPANY,                                            Judge.
    Defendant-Appellee.

                                         ORDER

       Stanley Smith claims that Union Pacific promised him that he would be reinstated as
an engineer after receiving treatment for alcoholism. After successful treatment, and upon
learning that Union Pacific had no plans to reinstate him, he filed a charge of discrimination
and sued under the Americans with Disabilities Act, 42 U.S.C. § 12101 et seq. The district
court determined that his charge was untimely and dismissed his complaint with prejudice.
Smith appeals, arguing that his charge was timely and, in the alternative, that dismissal
should have been without prejudice. We conclude that, although dismissal was proper, it
should have been without prejudice because Smith may be able to cure the deficiencies in
the complaint and surmount the company’s affirmative defense of untimeliness.
No. 11-2750                                                                               Page 2

        We construe the allegations in the complaint in the light most favorable to Smith. See
Golden v. Helen Sigman & Assocs., Ltd., 

, 360 (7th Cir. 2010). Smith alleged that in
1998 he began working for Union Pacific as an engineer. A year later he underwent
treatment for alcoholism and later returned to service. He voluntarily enrolled in an
outpatient treatment program at Rush Behavioral Health Center in 2005, at which time
Union Pacific agreed to reinstate him after he completed the program. In 2006 he completed
treatment and sought reinstatement, but the company balked. In 2009 Smith filed a charge
of discrimination with the EEOC, alleging disability discrimination due to alcoholism. See
42 U.S.C. §§ 12102(1), 12114(c)(4). He received a right-to-sue letter and sued the company
under the ADA.

       After Union Pacific moved to dismiss the complaint under Federal Rule of Civil
Procedure 12(b)(6) and invoked the affirmative defense that Smith’s charge was untimely,
Smith filed a response brief supported by an affidavit. In his brief, Smith altered his
narrative and contended that the discovery rule extended the limitations period and
rendered his charge timely; he asserted that he did not discover until 2009 that the company
had deceived him by refusing to honor its 2006 agreement to return him to service after he
completed an additional treatment program. He also asserted an estoppel argument,
contending that Union Pacific required him to remain in treatment, while concealing
medical reports from him which revealed that additional treatment was unnecessary. Smith
asked the district court to deny the company’s motion to dismiss or, in the alternative, to
grant leave to amend.

        The district court granted Union Pacific’s motion to dismiss with prejudice. The
court found Smith’s charge of discrimination untimely because his complaint and affidavit
plainly reveal that he knew of the refusal to reinstate in 2006 and did not file his charge until
2009–well after the 300-day deadline for filing a charge. See 42 U.S.C. § 12117(a). The court
rejected Smith’s discovery-rule argument, identifying the beginning of the filing period as
2006–the time that Smith alleged in his complaint that he became aware of the refusal to
reinstate. The court also rejected Smith’s equitable-estoppel argument on grounds that
Smith had not pleaded that the company attempted to deceive him. The court did not
address the altered narrative that Smith advanced in his response brief.

        On appeal Smith first challenges the district court’s ruling that his charge of
discrimination was untimely. Under the discovery rule, he argues, the charge he filed in
2009 was timely because not until that year did he discover that the company had reneged
on its agreement in 2006 to reinstate him; in the intervening period, he asserts, the company
strung him along with false assurances of reinstatement.
No. 11-2750                                                                                Page 3

        Before litigating an unlawful employment practice under the ADA, an employee
must file a timely charge of discrimination with the EEOC. See 42 U.S.C. § 2000e-5(e)(1),
incorporated by 42 U.S.C. § 12117(a); Stepney v. Naperville Sch. Dist. 203, 

, 239 (7th
Cir. 2004). A plaintiff must file a charge within 300 days “after the alleged unlawful
employment practice occurred.” Chaudhry v. Nucor Steel-Indiana, 

(7th Cir. 2008).
The discovery rule postpones the beginning of the limitations period to the date when the
plaintiff discovers or should have discovered that he has been injured. Barry Aviation Inc. v.
Land O'Lakes Mun. Airport Com'n, 

, 688-89 (7th Cir. 2004); Clark v. City of
Braidwood, 

, 767 (7th Cir. 2003).

       The district court correctly determined that the discovery rule did not excuse Smith’s
untimelineness. As the court explained, the complaint says only that Smith discovered the
refusal to reinstate in 2006 and did not file his charge until 2009, well after the 300-day filing
period expired. See 

. Given these allegations, the face of the
complaint shows that the action is untimely. See United States v. Lewis, 

, 842 (7th
Cir. 2005). Although Smith advanced a new chronology in his response brief, the district
court correctly disregarded that chronology because it differs from the account he pleaded,
and he may not amend his complaint through the filing of a response brief. See Pirelli
Armstrong Tire Corp. Retiree Med. Benefits Trust v. Walgreen Comp., 

, 448 (7th Cir.
2011); Help At Home Inc. v. Medical Capital, L.L.C., 

, 752 (7th Cir. 2001).

        Smith next contends that district court erred in rejecting his argument that equitable
estoppel extended the period during which he could file his charge. He contends that the
company withheld medical records from him and required him to continue with treatment
that the records revealed was unnecessary. Equitable estoppel suspends the running of the
filing period when the defendant takes active steps to prevent the plaintiff from suing,

, including concealing evidence needed to determine the viability of a
claim. See 

. The district court, however, properly deemed
equitable estoppel inapplicable because Smith did not plead that the company deceived
him. Although Smith’s response brief offers such an account, the court correctly disregarded
that new account because the response brief paints a narrative different than that alleged in
his complaint. See Car Carriers, Inc. v. Ford Motor Co., 

, 1107 (7th Cir. 1984).

        Last Smith argues that, even if his complaint was deficient, the district court should
have granted him leave to amend under Federal Rule of Civil Procedure 15. Rule 15
ordinarily requires that leave to amend be granted at least once when there is a potentially
curable problem with the complaint. See Bausch v. Stryker Corp., 

, 562 (7th Cir.
2010). In this regard, Smith contends that the factual assertions advanced in his response
brief would trigger the discovery rule and establish equitable estoppel, curing the problem
of untimeliness.
No. 11-2750                                                                              Page 4

        Although dismissal was proper, the district court should have dismissed the
complaint without prejudice. We disfavor granting dismissal under Rule 12(b)(6) on
grounds of untimeliness, see Doe v. GTE Corp., 

, 657 (7th Cir. 2003); therefore
when a plaintiff is presented with the affirmative defense by way of a Rule 12(b)(6) motion,
the plaintiff is ordinarily entitled to at least one opportunity to cure the problem through
amendment of the pleadings. See Foster v. DeLuca, 

, 584 (7th Cir. 2008); Rudder v.
Williams, 

, *3 (D.C. Cir. Jan. 17, 2012); United States v. Corinthian Coll., 

, 995 (9th Cir. 2011). In his response brief to the district court and in his briefing
before us, Smith has advanced a chronology that, if marshaled in an amended complaint,
may render his charge of discrimination timely. Facts raised for the first time in plaintiff’s
opposition papers should be considered when determining whether to grant leave to amend
or to dismiss the complaint with or without prejudice. Broam v. Bogan, 

, 1026
n.2 (9th Cir. 2003). Moreover, Smith asserts, he discovered in 2009 that the company
deceived him in 2006 into believing that it would return him to service after he completed
an additional treatment program. From 2006 to 2010, the company required him to remain
in that program, while concealing medical records from him which showed that additional
treatment was not necessary. When he discovered the company’s deception, he filed a
charge of discrimination. Taking these assertions as true, Smith’s contentions under the
discovery rule and equitable estoppel are colorable, sufficient to pass the pleading stage. See

; 

; Artis v. Hitachi Zosen, 

, 1144 (7th
Cir. 1992). The district court was required to consider this new chronology when gauging
whether any deficiencies in the complaint could be cured. See Indep. Trust Corp. v. Stewart
Info. Serv. Corp., 

, 943-44 (7th Cir. 2012); Rodi v. S. New England Sch. of Law, 

, 20 (1st Cir. 2004).

        We conclude that the district court properly dismissed the complaint. Dismissal,
however, should have been without prejudice, so that Smith could amend his complaint by
pleading the facts asserted in his response brief. Accordingly, we VACATE in part the
district court’s order dismissing Smith’s suit with prejudice and REMAND for further
proceedings consistent with this decision.