The Kansas City Chiefs have a new backup quarterback in the building this offseason. After spending 11 years with five different NFL clubs, Blaine Gabbert has returned to the state of Missouri to back up Patrick Mahomes with the Chiefs. With 115 games played during his career, Gabbert brings a certain veteran prowess to the quarterback room that only Mahomes shares. Speaking to reporters following the team’s third OTA practice, Andy Reid delved into his first impressions of the former Mizzou standout. “He’s smart. He’s bigger than I thought he was. (He’s) a big kid,” Reid said of Gabbert. “(He)…