Ricketts debuted on February 10, 2010 tossing three scoreless innings to beat the Florida Atlantic Owls.[6] She was named Second-Team National Fastpitch Coaches' Association All-American along with First-Team All-Big 12 honors.[7][8] As a freshman, she would break the record for strikeout ratio and then rank second for strikeouts overall at the school. Ricketts would lead the team into a Super Regional with the Washington Huskies and opened the series by beating National Player of The Year Danielle Lawrie before dropping the next two to be eliminated that year.
In her sophomore year, Ricketts would be named a First-Team All-American and earned her second conference honors.[9] Ricketts would break her own and set the school record for strikeout ratio with a career best 11.1 per 7-innings. She also broke the school strikeouts record, which now ranks second all-time.
On April 16, 2011, Ricketts lost a 9-inning contest vs. the Missouri Tigers and combined with Tiger pitcher Chelsea Thomas to record 33 strikeouts, an NCAA top-10 record.[10] In the NCAA tournament, the Sooners opened up that year against the Iona Gaels and Ricketts set a career and school high with 19 strikeouts in regulation, winning 7-1 on May 20.[11] The Sooners made the Women's College World Series that year by defeating the Arizona Wildcats but did not win a game.
Ricketts fired a perfect game over the Kansas Jayhawks on March 30 and struck out 10 batters to cross the 1,000 career benchmark, becoming one of the elite to reach that milestone in three seasons.[15] On May 19, Ricketts hit a grand slam to help reach a career high with 6 RBIs vs. the Lehigh Mountain Hawks.[16] At that year's WCWS on June 1, for her second game Ricketts pitched a 16-strikeout, 2 hit shutout over the No.1 California Golden Bears.[17] The Sooners would go on to defeat the defending champs to meet the Alabama Crimson Tide in the championship final. Ricketts won game one but then lost back-to-back games to drop the series. Ricketts would be named All-Tournament for her performance, tying the third best record for WCWS strikeouts with 64.[18]
For a final season, Ricketts claimed her fourth First Team all-conference and third First-Team and fourth overall All-American honors, simultaneously winning Big 12 Pitcher of the Year.[19][20] She would also earn her second USA Softball Collegiate Player of the Year and Honda Sports Award for softball to accompany the Honda Cup Award.[21][22] Ricketts had a career best in shutouts and winning percentage with a near perfect season while also throwing 6 no-hitters, a top-5 NCAA record for a single season.
February 9, 2013 she won her 100th game, no-hitting the Oregon Ducks.[23] Beginning on March 27-June 3, she had a career best 21 game win streak. Ricketts led her team to a No. 1 seed and culminated in winning the National Championship by besting the Tennessee Lady Vols in a 12-inning game one and then driving in all the runs, three of them the winning runs coming via her 50th career home run off Ivy Renfroe, in game two to seal the title. This would give her the Most Outstanding Player Award and her second All-Tournament recognition.[24]
Ricketts would also become one of the most prolific and winning pitchers in WCWS history going 8-4 with 112 strikeouts and allowing 19 earned runs in 80.1 inning for a 1.00 WHIP in three trips.[25] For her career she holds the school records in wins, strikeouts, shutouts, innings pitched and strikeout ratio.[26] In the Big 12 she ranks second in career wins, strikeouts and shutouts, third in strikeout ratio, fourth in innings and 7th in ERA; offensively she stands third in walks, fifth in home runs and 10th in slugging percentage.[27] In all of the NCAA she is 7th in wins all-time.[28]
