Szymanski was considered the No. 1 kicker in the nation out of high school, going to Texas A&M for two years before transferring to SMU. He was with Kansas City in the offseason and training camp, but was cut before the regular season. Szymanski also punted in college, but he's only listed on the roster as a kicker so it's unclear whether he's meant to provide depth for Dustin Colquitt.
It's a bit of an interesting move, as kicker and punters aren't typically signed to practice squads: those roster spots are normally for position players who can provide depth in case of injuries and help replicate opposing team's strategies on scout teams, which isn't really the case for kickers.
Succop hasn't had a poor year either, connecting on all but three of his 23 field goal attempts, good for the 15th-best percentage in the league. However, one of those misses was a 33-yarder in a game against the Pittsburgh Steelers that eventually went into overtime, but he later redeemed himself that game by nailing a 46-yarder at the end of regulation. Szymanski would appear to be a less accurate kicker than Succop, having hit only 35-of-58 attempts in college, although some of that is likely due to wider hashmarks on the field, although he did hit a 61-yarder in college while Succop's career long is 54.