Personally, Id sign Tex. The guy is just entering his prime, has stayed VERY durable (including playing all 162 games in 2005 and 2006) and has been productive regardless of what league he plays in. Plus, he plays sick defense.
I'm just saying this FO will always look within the organization first to fill a need if there is a guy on the horizon, and in this case, there is.
But like bosoxnation said, if Ortiz continues to decline, there will be a spot for both Lars and Tex once Papi's contract is up.