"x x x.
With the aforesaid pleadings submitted by petitioner, together with the corresponding pleadings filed by respondent, the LA and the NLRC declared the dismissal of respondent illegal. These decisions were premised on the finding that there was an employer-employee relationship.  Nowhere in said pleadings did petitioner deny the existence of said relationship. Rather, the line of its defense impliedly admitted said relationship. The issue of illegal dismissal would have been irrelevant had there been no employer-employee relationship in the first place.
It was only in petitioner’s Petition for Certiorari before the CA did it impute liability on DFP as respondent’s direct employer and as the entity who conducted the investigation and initiated respondent’s termination proceedings. Obviously, petitioner changed its theory when it elevated the NLRC decision to the CA. The appellate court, therefore, aptly refused to consider the new theory offered by petitioner in its petition. As the object of the pleadings is to draw the lines of battle, so to speak, between the litigants, and to indicate fairly the nature of the claims or defenses of both parties, a party cannot subsequently take a position contrary to, or inconsistent, with its pleadings. It is a matter of law that when a party adopts a particular theory and the case is tried and decided upon that theory in the court below, he will not be permitted to change his theory on appeal. The case will be reviewed and decided on that theory and not approached and resolved from a different point of view.
The review of labor cases is confined to questions of jurisdiction or grave abuse of discretion.The alleged absence of employer-employee relationship cannot be raised for the first time on appeal.The resolution of this issue requires the admission and calibration of evidence and the LA and the NLRC did not pass upon it in their decisions. We cannot permit petitioner to change its theory on appeal. It would be unfair to the adverse party who would have no more opportunity to present further evidence, material to the new theory, which it could have done had it been aware earlier of the new theory before the LA and the NLRC. More so in this case as the supposed employer of respondent which is DFP was not and is not a party to the present case.
In Pamplona Plantation Company v. Acosta, petitioner therein raised for the first time in its appeal to the NLRC that respondents therein were not its employees but of another company. In brushing aside this defense, the Court held:
x x x Petitioner is estopped from denying that respondents worked for it. In the first place, it never raised this defense in the proceedings before the Labor Arbiter. Notably, the defense it raised pertained to the nature of respondents’ employment, i.e., whether they are seasonal employees, contractors, or worked under thepakyaw system. Thus, in its Position Paper, petitioner alleged that some of the respondents are coconut filers and copra hookers or sakadors; some are seasonal employees who worked as scoopers or lugiteros; some are contractors; and some worked under the pakyaw system. In support of these allegations, petitioner even presented the company’s payroll which will allegedly prove its allegations.
By setting forth these defenses, petitioner, in effect, admitted that respondents worked for it, albeit in different capacities. Such allegations are negative pregnant – denials pregnant with the admission of the substantial facts in the pleading responded to which are not squarely denied, and amounts to an acknowledgment that respondents were indeed employed by petitioner.  (Emphasis supplied.)
Also in Telephone Engineering & Service Co., Inc. v. WCC, et al., the Court held that the lack of employer-employee relationship is a matter of defense that the employer should properly raise in the proceedings below. The determination of this relationship involves a finding of fact, which is conclusive and binding and not subject to review by this Court.
In this case, petitioner insisted that respondent was dismissed from employment for cause and after the observance of the proper procedure for termination. Consequently, petitioner cannot now deny that respondent is its employee. While indeed, jurisdiction cannot be conferred by acts or omission of the parties, petitioner’s belated denial that it is the employer of respondent is obviously an afterthought, a devise to defeat the law and evade its obligations.
It is a fundamental rule of procedure that higher courts are precluded from entertaining matters neither alleged in the pleadings nor raised during the proceedings below, but ventilated for the first time only in a motion for reconsideration or on appeal. Petitioner is bound by its submissions that respondent is its employee and it should not be permitted to change its theory. Such change of theory cannot be tolerated on appeal, not due to the strict application of procedural rules, but as a matter of fairness.
As to the legality of respondent’s dismissal, it is well settled that under Rule 45 of the Rules of Court, only questions of law may be raised, the reason being that this Court is not a trier of facts, and it is not for this Court to reexamine and reevaluate the evidence on record. Findings of fact and conclusions of the Labor Arbiter as well as those of the NLRC or, for that matter, any other adjudicative body which can be considered as a trier of facts on specific matters within its field of expertise, should be considered as binding and conclusive upon the appellate courts.
x x x."