Yeah, and If I remember correctly he would not take charge of the team thus was deactivated the final few games, then released that off-season
week 2- Bucs win 31-14 over Saints.  Garcia boasts a 145.8 QB rating, throws for 243 yards and tosses 2 TDs.  He tosses a 40 some odd yard bomb to Galloway to get the Bucs inside the 10 yard line, setting up a Caddy TD..  On another, he rushes to the Saints 1 yard line, setting up another Caddy TD.  NO TURNOVERS
Week 3-Bucs win 24-3 over Rams.  Earnest Graham was the hero here, but we were only up 10-3 late in the 4th quarter and Garcia NOT turning the ball over was huge here.  Afterall when you have  QB handing the other team points, a 10-3 is not as comfortable as you think.
Week 4-Bucs win 20-7 over Carolina.  NO TURNOVERS by Garcia and he rushed for a Touchdown.  The defense played huge here, but once again no short field to defend on turnovers.
Week 6-Bucs win 13-10 over Titans.  Garcia has a QB rating in the 100s and throws for over 274 yards with a touchdown pass.  If that isn't enough he leads the team in a tie game late in the 4th on the game winning field goal drive.
Week 9-Bucs win 17-10 over Arizona.  Garcia has a QB rating of 96.7 with a TD pass.  The Bucs D was sufficating, but NO TURNOVERS from Garcia....
Week 11-Bucs beat Atlanta 31-7.  Garcia has a 110 QB rating with 2 touchdown pases.  No turnovers.
Week 12-Bucs win 19-13 over Washington.  Garcia had all of 4 pass attempts in this game but Gruden wasn't confident enough in Gradkowski or McCown(McCown was 3rd QB but in the 4th Quarter the 3rd QB can come in and play-hell just have to play the rest of the game)  The D came up huge in this game
Week 15-Bucs win 37-3.  Looks like we could have QBed this game and won, Leftwich was just horrible this game.
The next game San Fran, Garcia doesnt even play a full 2 quarters and throws for 196 yards with a TD pass and a rating of 109.
NOW let's rewind and see what McCown may have done.  We will never know, but let's say he continues with his average of 1-2 turnovers a game with 1 TD pass, alonmg with giving the other teams points.
Week 2-Saints- Bucs win 31-14 with Jeff.  Take away 4 TDs Jeff set up, add in 2 TDs McCown would probably account for and give the Saints another 7 since it looks like McCown would give them a pick 6 somewhere down the road or atleast set them up nice.  Final.  Saints win 21-17.
Week 3- Rams- Bucs win 24-3 with Jeff.  Add a TD McCown would get, but also add a TD to the Rams off a turnover set up by McCown.  Take away atleast one Earnest Graham TD considering the game would be close and we would probably throw th eball.  Final.  Bucs win 24-10
Week 4-Panthers- Bucs win 20-7 with Jeff.  Take away Garcia's rushing TD, add a TD by McCown, add 7 Pts to Panthers off a McCown turnover.  Bucs win 20-14
Week 6-Titans-Bucs win 13-10 with Jeff.  Take away TD set up along with field goal set up.  Add McCown TD and a Titans TD.  Titans win 17-10.
Week 9-Arizona-Bucs win 17-10 with Jeff.  Take away TD set up by Jeff, add TD by McCown, add 1 TD for other team due to McCown turnovers.  Game tied at 17-17, but I'll be nice and say we win it in OT 20-17.
Week 11-Atlanta-Bucs win 31-7.  Take away two TDs by Garcia, add one by McCown, add 7 to Atlanta.  Bucs win 24-14.
Week 12-Redskins-Bucs win 19-13 with Jeff.  If the 49ers could get 14 pts from McCown, I'd say hed struggle with Washington.  Bucs would probably lose this one 20-19 if Gradkowski or McCown played in this game.
So I'd say with McCown we'd be 6-10 and in 3rd place in the division.  But hey we'd be better in the long run.  Now let me here how you think we'd be 12-4 with McCown last season, especially when he went 1-3 on his own.