When Oswalt left the Astros in 2010, both his wins (143) and strikeouts totals (1,593) ranked second in franchise history to Joe Niekro (144) and Nolan Ryan (1,866), respectively.

[4] At Weir High School, Oswalt played defensive back and wide receiver on the football team, which won a state title his senior year.

Convinced that Oswalt's anonymity kept him hidden from other teams, the Astros allowed him to drop into the 23rd round of the 1996 MLB draft.

[1] Oswalt would eventually become the latest-drafted player to lead his draft class in career Baseball-Reference Wins Above Replacement as of 2019[update].

[7] During the 1999 season, when Oswalt was with the Class A Michigan Battle Cats in the Midwest League, he began suffering pain in his upper shoulder.

The truck's electric current flowed through Oswalt's body, and consequently the muscles in his hand tightened on the spark plug wire.

In Olympic baseball competition, Oswalt pitched in the semi-finals against South Korea, a game that the U.S. won with a walk-off home run by Doug Mientkiewicz en route to their gold medal finish.

[10] In 2001, Oswalt started the season with the Triple-A New Orleans Zephyrs, where he went 2–3 before being called up to the MLB when left-hander Wayne Franklin was optioned down.

He pitched 24 consecutive scoreless innings before giving up a home run to Andrés Galarraga of the San Francisco Giants.

[11] From July 27 to September 8, he won a then-club record 9 straight starts before getting a no-decision in an extra innings' Astros loss to the St. Louis Cardinals.

In 2005, Oswalt threw a career-high 2412⁄3 innings, striking out 184 batters and only walking 48 on the way to his second consecutive 20-win season – the first Astro to do so since Joe Niekro in 1979–80.

Oswalt went 15–8 in 2006 and was named to his second consecutive All-Star team and his final ERA led NL (2.98), and also struck out 166 batters while walking 38.

[14] On August 29, 2006, Oswalt's 29th birthday, he signed a five-year extension with the Astros totaling $73 million with an option for a 6th year.

On September 18, while pitching against the Cincinnati Reds, Oswalt recorded his 1,000th strikeout, becoming the eighth player in Astros history to reach the milestone.

Before the 2007 season, Roy Oswalt received the second-highest Pitcher Player Value Ranking from Sports Illustrated Baseball Preview Edition.

He was rated the best in the NL ahead of Brandon Webb and Chris Carpenter, and was only below the 2006 Triple Crown winner Johan Santana.

On August 13, 2007, Sports Illustrated named Oswalt as one of the top five pitchers (along with Santana, Roy Halladay, Jake Peavy, and Justin Verlander).

[16] On September 26, 2007, it was reported that Oswalt was suffering from pain in his left side and it was decided to shut him down for the remainder of the season so as not to risk a more serious injury.

Although he started off the 2008 season slowly (0–3, 9.00 ERA), a solid second half helped Oswalt reach his highest win total since 2005.

He was the winning pitcher in the contest versus the Netherlands, but was pulled from the semifinal against Japan in the fourth inning after giving up 6 runs.

In a game against the Houston Astros, Phillies' first baseman Ryan Howard was ejected after arguing a checked swing to end the bottom of the 14th inning.

[21] On September 12, Oswalt pitched his first complete game as a Phillie in a 3–0 win against the New York Mets, allowing four hits and striking out six.

In the 2010 NLCS against the San Francisco Giants, Oswalt won Game 2 by allowing only one run in eight innings, which was his ninth postseason start without a loss.

However, he could only get two outs in the inning as Oswalt allowed two hits before Juan Uribe drove the winning run from third base on a sacrifice fly.

Going into the 2011 season, the Phillies' top four pitchers (Roy Halladay, Cliff Lee, Oswalt, and Cole Hamels) were widely touted as constituting one of the best starting rotations in history.

[23] After a strong start to the 2011 season, Oswalt took a leave of absence from the Phillies on April 27, 2011, citing "personal reasons", namely to check on his family and home after a series of devastating tornadoes in Mississippi.

ESPN's Jayson Stark reported that Oswalt, only 34 years old and up to that point an elite pitcher, was holding out for the hope of a large salary from a team relatively close to his hometown of Weir, Mississippi.

[27] On August 23, Oswalt made a spot start against the Tampa Bay Rays to give Matt Harrison an extra day of rest.

[29] He made his Rockies debut on June 20 against the Washington Nationals, pitching 5 innings and giving up 4 earned runs on 9 hits with 11 strikeouts.

[30][31] Oswalt, along with former teammate Lance Berkman signed a one-day contract with Houston to officially retire as an Astro on April 5, 2014.