Complex sentence: He started as quarterback for the Texas Longhorns for almost 2½ seasons, 1985-87 during which time he established 14 UT records, among them most passing yards in a season (2,233) in 1986, and most passing yards over a career (4,735).
Split into simpler sentences: He started as quarterback for the Texas Longhorns for almost 2½ seasons, 1985-87. Stafford established numerous UT records during his collegiate career, among them most passing yards in a season (2,233) in 1986, and most passing yards over a career (4,735).