Two seasons ago, Drew Lock made his first career start as Missouri’s quarterback in the fifth game of his freshman season.

Lock is now one of the SEC’s most seasoned quarterbacks and, the way Tennessee coach Butch Jones sees it, one of the league’s best. Lock will make his 30th career start when the Tigers (4-5, 1-4 SEC) host the Vols (4-5, 0-5) on Saturday (7:30 p.m. ET, SEC Network).

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“He plays with great confidence,” Jones said Monday. “He has moxie. He has swagger. … He’s going to play for a long time on Sundays.”

LSU’s Danny Etling is the only active SEC quarterback with more career starts than Lock, and some of Etling’s starts came while he was at Purdue.

Perhaps Tennessee quarterback Jarrett Guarantano’s career path will follow that of Lock’s.

Guarantano took over as UT’s starting quarterback in the sixth game of his freshman year. The comparison isn’t exact. Guarantano is a redshirt freshman. Lock was a true freshman when Maty Mauk’s suspension thrust him into the starting role.

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Guarantano is experiencing a rookie season full of ups and downs, much like the one Lock endured in 2015.

Fast forward to his junior season, though, and Lock touts a 60.7 percent completion rate. He leads the SEC with 2,795 passing yards and leads the nation with 31 passing touchdowns.

He’ll pose the toughest challenge to date for Tennessee’s pass defense, which is allowing just 150 yards per game, good for fourth nationally.

“He has as quick of a release as anybody we have faced. … He can make all the throws, has a live arm,” Jones said of Lock.

“But I think the big thing is, you can’t get to him,” Jones added, referencing the fact that Missouri has surrendered just eight sacks this season.

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Lock’s trademark is his arm strength. He throws arguably the best deep ball in the SEC.

Guarantano’s X-factor is his mobility, but that comes into question this weekend. He played less than half of Saturday’s game against Southern Mississippi because of a right ankle injury.

Jones on Monday listed Guarantano as probable for Saturday’s game.

“I was really encouraged today with Jarrett’s progress,” Jones said.

Guarantano’s injury comes at a time when he was showing progress after a couple of shaky games. Guarantano completed nine of 13 passes against Southern Miss after completing 18 of 23 the week before against Kentucky.

“I thought Saturday, I was really pleased with the rhythm, the spacing, the timing of the throw game,” Jones said. “He was much more decisive in the throws. He seemed a lot more confident throwing off the platform in the pocket, understanding where he was going with the football, whether it was a post-snap read or going through his progressions once the ball was snapped.

“I thought he really, really showed great progress.”

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If Guarantano can’t go, freshman Will McBride will have the reins. McBride made his debut in the 24-10 win over Southern Miss and completed one of eight passes, though he wasn’t helped by a few drops.

“This young man was excited to play, and his family was excited that he was playing,” Jones said, when asked about McBride’s redshirt being burned.

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McBride opened the season as the third-string quarterback but shuffled up the depth chart after Quinten Dormady, who opened the season as the starter, needed season-ending shoulder surgery.

Jones said McBride's family was at home in Texas on Saturday celebrating the birthday of his younger brother, Michael, and watching the game.

“All of a sudden, it kind of turned into a Will McBride watch party," Jones said. "The family was ecstatic and excited to be able to turn the birthday party into watching their son and their brother play. That was pretty neat.”