Tex. R. Civ. P. 193.6

Summary

(a) Exclusion of Evidence and Exceptions. A party who fails to make, amend, or supplement a discovery response, including a required disclosure, in a timely manner may not introduce in evidence the material or information that was not timely disclosed, or offer the testimony of a witness (other than a named party) who was not timely identified, unless the court finds that:

(1) there was good cause for the failure to timely make, amend, or supplement the discovery response; or

(2) the failure to timely make, amend, or supplement the discovery response will not unfairly surprise or unfairly prejudice the other parties.

(b) Burden of Establishing Exception. The burden of establishing good cause or the lack of unfair surprise or unfair prejudice is on the party seeking to introduce the evidence or call the witness. A finding of good cause or of the lack of unfair surprise or unfair prejudice must be supported by the record.