Just something I came across while doing research for Wikipedia, and while it has been discussed in some capacity elsewhere, I'm not sure if it has ever been discussed as early as this, particularly as this would be during the late Winter, early Spring of 1911. Can't give my thoughts just now though other then, arguably, it benefits Taft in the short-term. Source here: (link)
WANTED TO FIGHT MEXICO
Roosevelt Said To Have Offered His Services To Taft.
Washington, Feb. 26. - The announcement of Col. Roosevelt's willingness to accept the Presidential nomination, and his consequent open break with President Taft, was declared here tonight to have removed a picturesque possibility in connection with the threatened trouble in Mexico.
Senators who pretend to be conversant with the facts stated that when the Madero revolution was at its height and the possibility of American intervention was being discussed, Col. Roosevelt wrote a letter to President Taft volunteering to head a regiment of cavalry which was to be in the forefront of the invading force.
Col. Roosevelt, it is said, stipulated that his subordinate officers were to be of his own choosing, and went so far as to name some of the men he would select. These included Col. Cecil A. Lyon, Republican National Committeeman of Texas; "Jack" Abernathy, the wolf-strangling ex-Marshal of Oklahoma; Sloan Simpson of Texas, a "rough rider"; Secret Service Agent James Sloan, Jr., now with President Taft, and several members of the old Rough Rider regiment of Cuban war fame.
Col. Roosevelt at that time, it is said, stated it as his highest ambition to be again in the saddle in time of war.
The Colonel's letter to President Taft was addressed "Dear Will," according to those who say they saw it, and President Taft's reply was addressed "Dear Theodore." It stated, according to reports, that the Colonel's proposal "was very interesting, indeed," but that the possibility of American intervention was too remote a contingency to be considered at the time in any way.