231 F.3d 396 (7th Cir. 2000)
Arlie Leonberger, Plaintiff-Appellant,v.Martin Marietta Materials, Inc., Defendant-Appellee.
No. 99-4294
In the  United States Court of Appeals  For the Seventh Circuit
Argued June 5, 2000Decided October 26, 2000

Appeal from the United States District Court for the Southern District of Illinois.  No. 98-CV-4313-JPG--J. Phil Gilbert, Judge.
Before Easterbrook, Diane P. Wood, and Evans, Circuit  Judges.
Diane P. Wood, Circuit Judge.


1
Arlie Leonberger  suffers from sleep apnea, a serious disorder that  causes a person to stop breathing for brief  periods of time while asleep; the oxygen  deprivation that results disrupts the person's  normal sleep cycle, leaving the individual very  tired and with a tendency to fall asleep during  the day. Beginning in 1967, Leonberger had a job  working in a rock quarry that was eventually  owned by the defendant, Martin Marietta  Materials, Inc. (Martin). Martin became concerned  about Leonberger's tendency to "nod off" on the  job after it received complaints to that effect.  After efforts to obtain medical treatment failed  (for reasons we detail below), Martin fired him.  Leonberger sued under the Americans with  Disabilities Act ("ADA"), 42 U.S.C. sec.sec.  12101 et seq., but the district court granted  summary judgment for Martin. We agree that  Leonberger has not pointed to any triable issue  of fact and is not entitled to judgment. We  therefore affirm.


2
* The principal job Leonberger performed for  Martin was that of "yard load operator," which  required him to operate heavy machinery used to  load trucks with rock and aggregate for shipment.  On occasion, he also performed certain welding  duties. His direct supervisor was Bill Austin,  who reported to the quarry manager, Mose Frailey.


3
At some point, Frailey began to observe  Leonberger sleeping on the job. Leonberger  objected to that characterization of his  behavior, claiming instead that he simply chose  to "nod off" at times when there was nothing to  do because he was waiting for more trucks to  arrive. He told Frailey that he could stay awake  if he kept busy. It was then that Frailey  assigned Leonberger the welding duties, but the  experiment was not successful. A co-worker  reported to Frailey that Leonberger was sleeping  again, this time while on welding duty. Other  complaints about Leonberger's sleeping also  reached Frailey and Austin.


4
In addition to his job at Martin, Leonberger  ran a small fishing business at which he bought  and sold fish. He spent three or four hours a day  there. At other times in his life, Leonberger had  held jobs such as farming, truck driving,  maintenance work, and auto repair.


5
Concerned about Leonberger's persistent "nodding  off," Frailey and Austin went to the fishing  store in September 1997 to discuss the situation  with him. They suggested that he take a leave of  absence so that he could get his sleeping problem  treated, and Frailey volunteered to help him find  an appropriate doctor. Frailey also informed  Leonberger that under Martin's medical leave  policy, Leonberger would have up to six months of  leave time available to him. Leonberger signed an  acknowledgement form, and on September 15, 1997,  he filled out a written request to take the leave  of absence.


6
True to his word, Frailey put Leonberger in  touch with a Dr. Iyer, who began treating  Leonberger's condition. Dr. Iyer told Leonberger  that one treatment option involved surgery, but  Leonberger refused to consider that. An earlier  effort to use some type of machine to assist in  his night-time breathing had also failed.  Leonberger remained under Dr. Iyer's care,  nevertheless. After four months of his leave had  gone by, Frailey spoke with him and reminded him  that his medical leave would expire in March  1998. Martin sent him a letter on February 2,  1998, that specified March 5, 1998, as the final  day for his medical benefits. March 5 came and  went, and on March 13, after Leonberger had  failed to return to work with a doctor's release,  Martin terminated him. Also on March 13, Martin  received a note from Dr. Iyer stating that  Leonberger had a "significant sleep problem" that  had "not improved with treatment," and that the  problem was "interfering with his ability to  work."

II

7
Originally, Leonberger's complaint alleged only  that Martin had failed to accommodate his  disability, in violation of the ADA. After Martin  filed a motion for summary judgment on that  theory, the district court granted Leonberger  permission to amend his complaint. The amended  complaint abandoned the accommodation claim and  substituted a claim that Martin had discriminated  against him by terminating him because of his  disability. He also tried to argue, through his  materials on Martin's new summary judgment motion  directed to the discrimination claim, that Martin  had discriminated against him by "forcing" him to  take the medical leave. On appeal he has fleshed  out that theory as well. This latter theory seems  to be a sort of constructive discharge notion by  compelling Leonberger to go on medical leave, Martin ensured his eventual discharge.  (Presumably this theory also entails the claim  that Martin knew that the doctor would be  unsuccessful at curing the sleep apnea, and thus  had simply set Leonberger up for a negative  medical note at the end of the leave.)


8
The parties have sparred over the question  whether Leonberger's alternative theory of  constructive discharge was properly before the  district court and thus properly before us.  Martin urges that it is not, while Leonberger  points out that it was, if nothing else,  litigated by consent because he addressed it  fully in his response to the motion for summary  judgment, and Martin presented its arguments on  this point in its reply. The mere fact that  Leonberger had not spelled out this aspect of his  termination theory in the pleadings did not  preclude him from supporting his discharge theory  with this evidence at the summary judgment stage.  We therefore consider both aspects of his  argument here.


9
On the merits, the only disputed issue was  whether Leonberger could show that he was a  qualified individual with a disability, as that  concept is defined in 42 U.S.C. sec. 12102(2).  Because the parties were proceeding under the  burden-shifting method of proof established in  McDonnell Douglas Corp. v. Green, 411 U.S. 792  (1973), this point logically might have been  considered at the prima facie case stage, element  one of which requires the plaintiff to show that  he is in the protected class. Perhaps in an  effort to avoid a protracted dispute over the  question whether Leonberger's qualifications had  to be assessed without considering his sleep  disorder, or perhaps because it was just more  straightforward, the district court chose to  assume that Leonberger had satisfied the prima  facie case and it asked instead whether  Leonberger had any evidence to show that Martin's  asserted reason for firing him was a pretext.


10
Martin said that it fired Leonberger because  (1) he failed to report to work before the  expiration of his medical leave with a doctor's  release, and (2) he failed to request an  extension of his leave time before the first  period expired. Leonberger presented some  evidence that might have rebutted the second  reason, since there was nothing in the medical  benefits plan that indicated that extensions were  possible. But he offered nothing to counter the  first point, and we frankly find it hard to  imagine what he could have said. Looking either  at the moment when Martin placed him on the leave  of absence or the moment when it fired him, it is  undisputed that Leonberger had been observed  either "sleeping" or "nodding off" on the job,  including while the front loader was in  operation. Martin took the position that it did  not want to incur the risks posed by having a  sleepy employee operate such a large and  potentially dangerous piece of equipment. We  often say that we do not, and cannot, impose our  own ideas of prudent business management on  employers; we can assess only the question  whether an employer has taken an action for a  forbidden reason. See e.g., Robin v. ESPO Eng'g  Corp., 200 F.3d 1081, 1091 (7th Cir. 2000). But  Martin hardly needs the benefit of that rule,  since an employee who is less than fully alert  could harm himself and others if he is operating  a front loader, or many other kinds of heavy  industrial equipment.


11
We add for the sake of completeness that  Leonberger himself testified that he chose to nod  off, in an effort to refute the idea that his  sleeping disorder was causing him to do so. But  it is hard to see how that claim advances his  case. Martin had no reason to care why Leonberger  was sleeping; it just didn't want people who were  groggy for any reason operating its machines. If  anything, this tends to reinforce Martin's  position that its action was a response to  Leonberger's performance of the job and was not  a product of discriminatory animus.


12
The judgment of the district court is Affirmed.

