A substandard pass rush stings in light of two transactions by Grigson in April. First, Indianapolis traded the underachieving pass rusher Jerry Hughes to Buffalo for linebacker Kelvin Sheppard, who is now a backup. Hughes was a disappointing first-round pick under the old Colts management, producing just five sacks in three seasons. But he is having a breakout season in Buffalo with eight sacks, and he ranks second among all 3-4 outside linebackers in a statistic created by Pro Football Focus known as pass rusher productivity.

Then Grigson spent the team’s first-round draft pick on Florida State defensive end Bjoern Werner. But Werner has barely been able to steal snaps from the underachieving Walden. According to Football Outsiders, Werner has had just 210 snaps and recorded only half a sack. In fact, Grigson’s entire rookie class has been underwhelming: Colts draft picks have been on the field for only 982 offensive or defensive snaps this season, with the third-round left guard Hugh Thornton (730 snaps) and Werner the only players with notable playing time.

Even one of last year’s successful decisions — trading a second-round pick for Miami cornerback Vontae Davis — has come into question. According to Pro Football Focus, quarterbacks have a 106.4 passer rating on throws to players covered by Davis, who has just one interception while allowing a league-leading eight touchdowns.

But the trade that might define the Grigson era was for Cleveland running back Trent Richardson. Richardson has struggled in Indianapolis — he is averaging 2.9 yards on 114 carries in 11 games — and will cost Indianapolis its first-round pick in the 2014 draft.

It was a curious decision on many levels. Using a first-round pick on a running back is rarely advised. No team used a first-round pick on a running back in April, and Richardson is the only running back selected in the top 25 in any of the last three drafts. Even if Richardson was going to be a star, were the Colts a star running back away from a Super Bowl? One could argue that no team in the pass-happy N.F.L. needs a great running back to win, and the Colts had many more pressing needs.

In particular, the offensive line needs help. Thornton, while a starter, has allowed 14 quarterback hits, according to Pro Football Focus, the most of any guard in the N.F.L. The right guard, Mike McGlynn, has been just as bad. The two rank among the bottom 10 starting guards, according to Pro Football Focus. Between them sits center Samson Satele, another mediocre blocker, who has allowed six sacks, tied for the most in the N.F.L. among centers. Grigson traded the backup center A.Q. Shipley