Appleby, a junior who started the Boilermakers' final seven games last season, hopes to become the first Purdue quarterback to lead the team in passing for two consecutive seasons since Curtis Painter - who has played in the NFL with Indianapolis, Baltimore and the New York Giants - in 2007 and 2008.
Appleby and the quarterback position was the focus of conversation Sunday at Purdue's Media Day.
Appleby replaced Danny Etling, who transferred to LSU this summer, after five games last season. In his first three starts, including an Oct. 4 victory at Illinois, Appleby completed 66.2 percent of his passes, including five for touchdowns, and averaged 188.7 yards in helping the Boilermakers average 35.7 points.
But he slumped badly in four November losses, completing only 48.2 percent of 166 attempts while passing for only four touchdowns and being intercepted seven times. Worse, the Boilermakers averaged only 15 points in those final four games, capping a 3-9 season and saddling coach Darrell Hazell with a 4-20 two-year record at Purdue.
Wanting to erase the memories of his four most recent starts, Appleby is eager to retain the starting position.
''That just goes into my process,'' Appleby said, ''My process is to control the things I can control. It's the work that I have put in during the offseason. It's working toward being the best player I can be. That process constantly is worked upon.
''I am happy with where I am. If I handle the things I can control, and stick to that each and every day, it is my process and I own it. Everything will take care of itself. I want to be process oriented and let results follow.''
Hazell has not targeted a date for picking the starting quarterback for the Marshall game. He will give Appleby, Blough and Sindelar opportunities to work with the No. 1 offense during the next three weeks.
''One of the most important things for us to find out about our quarterback is, `Will he take care of the football?' and `Can he make the makable plays?''' Hazell said. ''When we find that guy, we will be off and running.
''We have three very competent guys in camp that we think are very capable of winning a lot of football games. The biggest thing is, ''Can the guy step into the huddle and command respect?''
Considering Appleby is the only quarterback on Purdue's roster who ever has taken a snap or thrown a pass in a college game, he would appear to be the likely starter at Marshall.
But Blough was impressive in Purdue's spring game, and Sindelar was Kentucky's 2014 Mr. Football and was the state's Gatorade Player of the Year. Appleby respects the two young quarterbacks who will push him for the job.
''I am so blessed and so happy to have teammates like them,'' Appleby said. ''As a quarterback, you have to have full confidence that the guys behind you have your back. I don't have to look over my back and worry that someone has a hidden agenda.
''David is one of my best friends in the world. Elijah, in the six months that I have known him, has become one of my best friends.''