What happens when a treating physician “morphs” into an expert witness. The courts have held that the party offering expert testimony of a treating physician must comply with Rule 26(a)(2)(b) and provide opposing counsel with the expert’s report.

The court, in Gann v. DYNASPLINT SYSTEMS, INC., Dist. Court, D. Nevada 2013 stated:

Defendant also argues that Plaintiff violated Rule 26(a)(2)(B) by not providing any written report upon designation of Dr. Watson as an expert. In the Response (ECF No. 46), Plaintiff does not address this ground for precluding Dr. Watson’s testimony. Although not cited by Defendant, Rule 37 of the Federal Rules of Civil Procedure provides for sanctions where a party fails to provide information as required by Rule 26(a), including preclusion of witness testimony at trial. As noted by Defendant, the Ninth Circuit has held “that when a treating physician morphs into a witness hired to render expert opinions that go beyond the usual scope of a treating doctor’s testimony, the proponent of the testimony must comply with Rule 26(a)(2).” Goodman v. Staples The Office Superstore, LLC, 644 F.3d 817, 819-20 (9th Cir. 2011).