David Stephenson, AP
Missouri quarterback Maty Mauk scrambles for an opening during the first half of an NCAA college football game against Kentucky, Saturday, Sept. 26, 2015, in Lexington, Ky. (AP Photo/David Stephenson)

COLUMBIA, Mo. (AP) — Missouri suspended junior quarterback Maty Mauk for the rest of the season for disciplinary reasons, just six days after reinstating him.

The Tigers (4-4) play 24th-ranked Mississippi State (6-2) on Thursday night at home. Missouri will face BYU on Nov. 14 at Arrowhead Stadium.

Freshman Drew Lock has made four starts since Mauk was first suspended. Lock has completed 77-of-152 passes (50.7 percent) for 763 yards, three touchdowns and three interceptions in Mauk's absence. Mauk threw for 654 yards (with a 51.8 percent completion rate) with six touchdowns and four interceptions prior to his first suspension.

The school said in a news release Sunday that it will not discuss further details of Mauk's suspension. The first suspension was for a violation of program policies.

No matter who has played at quarterback, though, Missouri has struggled on offense this season. The Tigers average 277.6 yards per game — 126th nationally — and 14.9 points a contest, second-worst in the nation.

The Tigers have relied on a stout defense to keep them in games. Missouri is giving up just 282.1 yards per game (sixth nationally) and 12.5 points per contest, good enough for third in the country.