The cost of the NFL's battle with the NFLPA and New England Patriots over air pressure in footballs is rising, according to a report from Darren Rovell. The ESPN senior writer claimed legal fees for Deflategate are approaching $20 million with the NFL footing most of the bill.

According to Rovell's breakdown of the fees, the NFL has spent approximately $12.5 million on the controversy thus far. That amount includes approximately $2.5 million for the Wells Report and about $10 million in billable hours for multiple law firms working on the case.

Rovell also ran comparisons for billable hours for law firms retained by the NFLPA on behalf of quarterback Tom Brady, and the price tag for Brady's lawyers could cost the players' union about $5 million so far.

The Patriots might have the cheapest bill per Rovell, as he estimates the team spent $500,000 on miscellaneous items, including a lengthy public rebuttal to the Wells Report.

For those keeping track, the tab stands at $18 million combined from all sides, but Rovell said there could be another $2 million worth of expenses due to bills for document production, expert witnesses and so on.

The estimated $20 million price tag was not received well on Twitter.

The cost will likely continue to rise, however, as the two sides are scheduled to return to court Thursday for a hearing in the NFL's appeal.