TAMPA, FL — The Tampa Bay Buccaneers held their first day of rookie minicamp on Friday, officially playing football for the first time since the season ended in January. Tampa Bay's rookies, undrafted free agents and tryout players got to get their first reps during the offseason, build some chemistry with their new teammates and try their best to make an impression. Day 1 is typically a day to adjust to the learning curve and study playbooks and fundamentals, but there were still a few things to note and a few players who impressed. BucsGameday was live on-site as always — here are three things we saw from Day 1 of rookie minicamp: Rueben Bain Jr. impresses It's hard to evaluate players on the offensive and defensive line without pads, but there are some things, like explosiveness and pass-rushing moves that show out in person. Bain, Tampa Bay's first-round pick, showcased it all. Bain looked impressive doing individual drills, and it translated well to team drills.…