[1] Robertson pitched for the Low-A Utica Blue Sox and Single-A Kane County Cougars; with the latter he was 6–1 with a 2.29 ERA in eight starts.

Robertson returned to Kane County for the 2000 season but spent most of the year on the disabled list battling tendinitis in his left elbow.

At Portland Robertson amassed a 10–9 record with a 3.42 ERA, sufficient that Florida summoned him to the major league club in early September.

[2] Robertson made his Major League debut on September 7, 2002, for the Marlins, pitching 4+2⁄3 innings and allowing four earned runs in a 4–1 loss to the Pittsburgh Pirates at PNC Park.

The following January Florida traded Robertson along with Gary Knotts and Rob Henkel to the Detroit Tigers for Mark Redman and Jerrod Fuell.

[4] Robertson won his first major league game eleven days later, pitching five innings in an 8–4 victory over the Chicago White Sox.

While wearing a microphone for television, Robertson began stuffing his mouth with Big League Chew to encourage the Tigers to score, down 5–0.

[6] Robertson earned his first career postseason victory on October 10, 2006, by pitching five shutout innings against the Oakland Athletics in game 1 which helped launch the Detroit Tigers into their ALCS sweep of the A's and their first pennant since 1984.

[8] On August 22, 2008, Tigers manager Jim Leyland announced that Nate was being demoted to the bullpen due to ongoing trouble with his slider.

On September 9, 2010, Robertson was designated for assignment by the Phillies, a day after giving up 5 runs in 2⁄3 innings against the Marlins and nearly blowing a 10-run lead.