Rockies' Troy Tulowitzki out, external replacement coming?

The Rockies placed Troy Tulowitzki on the disabled list after learning he will be out till August with a wrist injury. The Rockies are four games back in the division, and the loss of Tulo hurts the Rockies chances of another midseason run. One NL source speculated that the Rockies could look to external options to fill in at shortstop, then providing infield depth when he returns. 

One possible option for the Rockies could be Cubs middle infielder Ryan Theriot. Theriot is not a long-term option for the Cubs, but could fit in nicely in a short term role with the Rockies. This way, the Cubs could work in Mike Fontenot, Jeff Baker, and maybe even Darwin Barney if they fall too far out of contention. Out of contention or not, the Cubs could likely net a solid prospect in return for Theriot. 

Another possible option would be to move Clint Barmes back to shortstop and trade for Diamondbacks second baseman Kelly Johnson. Johnson is hitting .270 with 13 home runs this season, but would probably come at a reduced rate considering he is hitting .251 since May 1st. 

Should the Rockies trade for a replacement or hope that in-house replacements can keep them afloat?