The quarterback carousel continues for Penn.

Keiffer Garton led the Quakers to a 27-13 victory at Columbia last Saturday, tossing two touchdowns in his first start since sitting out a couple of games due to an elbow injury.

But at Wednesday’s practice, Garton was not on the field.

He was on crutches.

The junior from Castle Rock, Colo., suffered an apparent knee sprain early in Tuesday’s practice and has not taken the field since.

“We caught a bad break [Tuesday] with him kind of getting hit and his knee flared up on him,” coach Al Bagnoli said. “We’ll see what happens Saturday.”

Garton is wearing a brace and is considered a game-time decision for the Quakers’ home showdown with Yale (3-2, 1-1 Ivy) tomorrow.

The Red and Blue (3-2, 2-0) may have inadvertently hedged their bets so far with senior Kyle Olson and sophomore John Hurley taking significant snaps earlier this year.

“Kyle will be playing,” Bagnoli said. “John Hurley’s ready. We have two guys that have game experience that are ready to go.”

Whoever is under center won’t have an easy time; the Bulldogs boast the Ivy League’s top scoring defense and are second to the Quakers against both the rush and the pass. (Penn’s second to Yale with 14.2 points allowed per game.)

This is old hat for both teams, considering the Quakers topped the stingy Bulldogs, 9-7, with three field goals last year in New Haven, Conn.

Such a defensive duel puts points “at a premium,” according to Bagnoli.

It also pits some of the league’s premier defenders on the same field.

Penn’s savvy ground game — complete with a healthy Lyle Marsh — has its toughest Ivy test yet. Marsh’s 58.4 yards per game could be cut down, as the Bulldogs are yielding just 84.0 rushing yards per game to opponents this season.

On the flip side, Yale is throwing at will, racking up over 217.2 pass yards per game. That’s good for second best in the Ancient Eight, while Penn’s 136.2 is dead last.

Such a performance may not continue with Penn’s secondary, led by All-American Chris Wynn and a surging Jonathan Moore, who already has three picks on the year.

“With our defense versus their defense it’s going to come down to which offense makes more plays,” Penn wide receiver Matt Tuten said.

Bagnoli added that the outcome may hinge on the special teams play and turnover differential.

The Quakers are riding a three-game winning streak, but they’ve yet to play the best in the League. Given Yale’s results, it’s also tough to determine where they stand in the rankings.

Although the Bulldogs share a 3-2 overall record with the Quakers, their victories may not be very telling of their abilities. Yale secured its three victories over opponents (Georgetown, Dartmouth and Lehigh) with a combined record of 1-17.

The Bulldogs lost 31-14 to Lafayette — which only beat Penn earlier this year in overtime by a field goal — and they also had a comeback against Cornell fall short, as they lost, 14-12, at home.

A Quakers’ victory would provide much-needed momentum heading into a road trip at Brown next weekend, but if Yale comes out on top, the Bulldogs can put to rest the idea that they’re only capable of winning against sub-par teams.