In baseball, as a senior, he was named the District MVP and posted a .410 batting average, hit seven home runs, and pitched his way to a 10–3 record and a 0.92 ERA with 132 strikeouts.

In 2006, Jennings pitched much better, ending the season with a 3.78 ERA, but had only a 9–13 record due to a lack of run support that ranked near the bottom of the league.

On December 12, 2006 the Rockies traded Jennings, along with Miguel Asencio, to the Houston Astros for Willy Taveras, Taylor Buchholz and Jason Hirsh.

Jennings ended up going on the DL after just six starts, all in April (missing the rest of the season), in which he struggled mightily.

During the 2009–2010 MLB offseason, Jennings was signed by the Oakland Athletics to a minor-league contract with an invite to spring training.

[8] On May 25, 2011, the Grand Prairie AirHogs of the American Association of Independent Professional Baseball signed Jennings to a contract for the remainder of their season.