[1][3] Upon passing the NFL Players Association (NFLPA) Contract Advisor Exam in July 2016, he developed SLG Sports & Entertainment as a division of the Sommer Law Group.
[CFLPA] To date, he has represented and serviced more than 30 NFL, CFL, and NCAA athletes on matters related to their playing, marketing, and post-playing career.
[1] Guminski first garnered media attention in April 2020, as the onset of the COVID-19 pandemic resulted in the cancellation of “pro days” across the United States for NFL and CFL draft prospects.
In an effort to mitigate the negative effects of the pandemic and to showcase Mathews’ talent, and the talent of several of Guminski's other clients, as well as numerous other local draft prospects, to professional teams, Guminski organized and contributed to the facilitation of an unofficial pro day for these athletes at the 424 Factory and a local practice field in Pittsburgh.
[7][8] Following the pro day, Guminski appeared on KDKA-FM 93.7 The Fan's The Hotline radio show, hosted by Paul Zeise, to discuss the pro day's organization and execution, as well as the broader effects of the COVID-19 pandemic on the NFL's operations, 2020 off-season and season schedule, draft prospects, and veteran players, as well as the operations of NFL and CFL agents.
[10][11][12] Guminski has assisted his collegiate clients in navigating the NCAA's recently changed NIL rules to facilitate personal branding and charitable initiatives, such as the organization and execution of Buffalo Bulls running back Dylan McDuffie’s December 2021 Holiday Toy Drive in collaboration with the Boys & Girls Club of Buffalo.