Pendleton grew up a Houston Astros fan.[1] He attended Kingwood High School from 1999 to 2002, where he played for the Kingwood Mustangs.[2] Pendleton earned All-District MVP as an accomplished pitcher and hitter.[1] He was drafted out of high school by the San Diego Padres in the 13th round of the 2002 MLB Draft, but did not sign.[3]
Pendleton was selected in the fourth round (139th overall) of the 2005 Major League Baseball Draft by the New York Yankees.[8] Shortly afterwards, Lance underwent Tommy John surgery.[9] Returning to the Yankees farm club in 2007, Lance played for 6 teams in 5 years, compiling a 32–22 record and a 3.39 cumulative ERA.[10] He was named a Mid-Season All-Star while with the Charleston RiverDogs in 2008. Playing for the Tampa Yankees in 2009, he was named Pitcher of the Week for the week of June 29 and was a Post-Season All-Star. In 2010, Pendleton was Pitcher of the Week for the week of July 26 and a Mid-Season All-Star while a member of the Trenton Thunder.[11]
He was claimed off waivers by the Astros in September 2011.[16] Allowing nine runs in 4+2⁄3 innings with the Astros, they outrighted him to the minor leagues following the season. As this was the second time he was outrighted, he had the option to opt for free agency, which he exercised.[17]
The Astros signed Pendleton to a minor league contract with an invitation to spring training for the 2012 season.[18] On March 30, 2012, Pendleton was released by the Houston Astros.[11]