In Jackson v. Workers' Compensation Appeal Board (Resources for Human Development), 877 A.2d 498 (Pa. Cmwlth. 2005), the employer's physician did not acknowledge that the claimant had a disabling knee injury, but testified "in the alternative and based on the assumption that [the claimant] had suffered a knee injury, that 'it resolved.'" Id. at 503 (quoting the WCJ Hr'g Tr. at 21). The physician's testimony was found to be competent. Id.