Non-competition provisions are generally enforceable in Texas, assuming that they are reasonable in their scope and provisions.
Quote Quoting Texas Business and Commercial Code, ยง 15.50
Criteria for Enforceability of Covenants Not To Compete
(a) Notwithstanding Section 15.05 of this code, and subject to any applicable provision of Subsection (b), a covenant not to compete is enforceable if it is ancillary to or part of an otherwise enforceable agreement at the time the agreement is made to the extent that it contains limitations as to time, geographical area, and scope of activity to be restrained that are reasonable and do not impose a greater restraint than is necessary to protect the goodwill or other business interest of the promisee.
There are additional provisions in that code section specifically pertaining to physicians.

Within those criteria, analysis is on a case-by-case basis, depending upon factors including duration, geographic scope, and the type of work affected by the agreement. The only information you provide is to time, and there are Texas cases upholding agreements which last from two to five years, so that of itself probably would not invalidate the agreement.

If you want a specific analysis, you should have the actual document reviewed by a Texas lawyer.