“Gee Gee, he’s a big play waiting to happen,” said freshman quarterback Keenan Reynolds. “If you give him the ball, you never know.” (Jonathan Newton/The Washington Post)

During what has become its defining game this year, the Navy football team trailed Air Force by eight points with nine minutes to play on Oct. 6 and was in danger of having its season unravel. What’s more, freshman Keenan Reynolds had taken over at quarterback for his first meaningful minutes, and the inhospitable crowd at Falcon Stadium was adding to the din.

So to help calm the situation, offensive coordinator Ivin Jasper called on senior slotback Gee Gee Greene, who turned a short reception into a 35-yard gain that moved the Midshipmen into Air Force territory. Four plays later, Navy tied the score at 21 before going on to win in overtime, 28-21, on a drive in which Greene carried twice for 11 yards, including a six-yard run to the 1-yard line.

The victory sparked a five-game winning streak, ensuring Navy of a winning season for the ninth time in 10 years. On Saturday in Philadelphia, the Midshipmen (7-4) will go for their 11th straight win over rival Army (2-9), a victory that would give them control of the Commander-in-Chief’s Trophy for the first time since 2009.

“Gee Gee, he’s a big play waiting to happen,” said Reynolds, who himself has accumulated his share of highlights this season. “If you give him the ball, you never know. He may take a two-yard pass and take it 40 like he did against Air Force. We will definitely give him the ball and get him out in space and let him do his thing.”

Greene is by far Navy’s leader in total yards per game this season, averaging 93.6 per game. His also is averaging 7.1 yards per carry, the second-highest single-season mark in program history.

On Saturday, Greene will be on the field for his last Army-Navy game, becoming among the select few at either institution who will be able to say he played in four installments of the rivalry. Part of Greene’s responsibilities as a senior has been to indoctrinate his younger teammates on what to expect from one of college football’s most storied rivalries.

In 2009, when the game was moved to the second Saturday in December so as not to conflict with conference championship games, Greene, then a plebe, was on the receiving end of that information in the weeks leading to kickoff. When he finally stepped onto the turf at Lincoln Financial Field that afternoon, Greene recalled a profound torrent of emotion.

Although Greene’s participation in that Army-Navy game was on special teams only, he was part of the celebration following the Midshipmen’s 17-3 victory. This year’s Army-Navy game will determine the winner of the Commander-in-Chief’s Trophy for the first time since 2005.

“I feel like my teammates count on me a lot to make plays, so I feel like I’m obligated,” Greene said, “even if that requires me just making blocks or just encouraging them and being there for my team.”

Like all the skill-position players in Navy’s triple-option offense, Greene takes special pride in his blocking, but opponents often are left grasping at air when trying to tackle one of the Midshipmen’s most elusive and durable runners. Greene leads Navy in rushing this season with 750 yards, and he has started 36 consecutive games dating from the 2010 season opener against Maryland.

This year, Greene had the most productive rushing game of his career with 150 yards and a touchdown on 16 carries and added three receptions for 39 yards in a 41-31 loss at Troy on Nov. 10. Two weeks earlier at East Carolina, Greene amassed 131 yards on 14 carries in a 56-28 win that was Navy’s fourth in a row.

“It’s weird because when we put on film from years ago, put the ’09 [Army-Navy] film on, it’s like, ‘There’s Gee Gee.’ I was like, ‘Wait a minute now,’ ” Jasper said. “So he’s been here forever. He’s made a lot of plays for us. As a coach you want to do the best you can to not only get a win for him but the rest of the seniors and all the guys. You want to send the kid out with a ‘W’ because he’s done so much for the program.”