Jim Nantz and Phil Simms are likely to shatter an NFL TV broadcasting record in 2014. Earlier this year, CBS acquired the rights to the new Thursday night NFL package. The network has already announced that Nantz and Simms will call the 7 Thursday night games on CBS, the 7 Thursday night games on NFL Network, and one of the Saturday games in week 16. That will put them at 15 games, but CBS also plans to use Nantz and Simms on "select" Sunday telecasts - presumably on many of the doubleheader weeks.
The expected workload for the CBS #1 crew leads into the question as to who holds the "record" in the category of most games worked in a single regular season by an NFL TV announcer. Using the historical pro football TV announcer listings at 506sports, the current record is 21 games. Frank Gifford reached this mark 4 times while OJ Simpson and Joe Namath did so once each - all for ABC.
So, if we conservatively assume that CBS assigns Nantz and Simms to a Sunday contest on 6 of the 9 CBS doubleheader weeks, then if they also work on opening Sunday and Thanksgiving Day, that would make 23 games which would easily set a new single season record. If CBS were to use them on all 8 of the "practical" doubleheader weeks (excluding week 16 due to the Saturday games), then the mark would reach 25. It will be interesting to see how this plays out.
<UPDATE 12/15/2014: Nantz and Simms will not call a week 16 Saturday game, but will work that Sunday instead, They also called a week 15 game during a CBS singleheader which, along with a week 17 game, will bring their season total to 26.>
Here is the complete list of announcers I found who called 19 or more games in a single regular season:
Nantz and Simms are among a group of announcers who have called 18 games in a season. In the era of the 17-week schedule, many of the announcers on the CBS and Fox #1 crews have called 18 (typically when receiving double-duty on Thanksgiving weekend). In 1993, the NFL had an 18-week schedule, but even though the #1 announcers doubled up on Turkey Day weekend, they got a week off elsewhere. Others who have maxed out at 18 include Pat Summerall, John Madden, Dick Stockton, Matt Millen, Troy Aikman, and Greg Gumbel.
Most of these marks were set when ABC had a 20-game package starting in 1978 and a 21-game package from 1983-86. Gifford called all of those games. Al Michaels missed 2 in 1986 while covering the baseball playoffs. Cris Collinsworth joined the club in 2013 when the NBC prime time package expanded to a 19-game schedule. Some other notable #1 announcers who have never reached 18 are Joe Buck (who annually misses games to cover the MLB playoffs) and Dick Enberg (who often had golf conflicts).