Saturday marks the Buffalo Bills' third preseason game as they're set to take on the Pittsburgh Steelers. It will also mark the third starting quarterback of the preseason.

EJ Manuel will be under the bright lights Saturday as he makes a final push to be considered as the regular season starter. He'll be without many of his top weapons as the Bills are slowly recovering from several recent injuries on the offensive side of the ball.

Here are three things to watch against the Steelers on Saturday in the team's final "meaningful" preseason game.

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How the quarterbacks perform

Manuel will be the starter, but Matt Cassel and Tyrod Taylor are also expected to see time with the first-team offense. Reports have indicated that Manuel is last in the competition and has no real shot of winning the job, but he'll get the start Saturday nonetheless. Manuel will need to set the world on fire in order to make a case to be the starter, something he hasn't really done since coming into the NFL. Taylor and Cassel have been consistent, with Tyrod making electric plays with his feet. Cassel was held out of the last preseason game, but with the season opener quickly approaching, he'll definitely see plenty of time on Saturday. How much time each quarterback gets will be telling and is something to keep an eye on. Whoever gets the most playing time could end up being the regular season starter.

Ronald Darby and the cornerbacks

It'd be hard to find a player that's been more up and down than rookie corner Ronald Darby. Against the Panthers, he struggled to find a groove and was targeted often. Against the Browns, however, Darby was a stud. He picked off two passes and defended two more, putting in the best performance of his young career. But which Darby will show up against the Steelers? That remains to be seen, yet the Bills are hoping it's the one that shined in the second game. Leodis McKelvin is still out with an injury, which has led to Darby and other corners seeing increased time. Nickell Robey and Ron Brooks will also get chances against the Steelers as they look to solidify a spot on the roster.

Nick O'Leary's final push at tight end

From the nation's top tight end, to sixth-round pick, to cut by the Bills: That's what could happen to Nick O'Leary. The former Florida State Seminole has been on the outside looking in for much training camp, with Rex Ryan even saying he's not sure if he'll make the 53-man roster. Granted, that wouldn't be unheard-of for a sixth-round pick, but O'Leary gets more attention than most players drafted at his spot. O'Leary is fourth on the depth chart behind Charles Clay, the surprising Marqueis Gray, and Matthew Mulligan, making him a long shot to make the team. If he gets any hint of playing time Saturday, he'll need to take full advantage.