The Patriots’ backup plan at tight end is gradually making progress. Jake Ballard is finally ready to hit the field, but the team is going to take it slow with him when the offseason program begins tomorrow at Gillette Stadium. Ballard tore his ACL in the Giants’ victory against the Patriots in Super Bowl XLVI, and he is recovering nicely. But without the need to get overly aggressive, the Pats are taking the cautious approach. The first two weeks of the offseason program are strictly limited to conditioning, and the following three weeks are “perfect play” drills, which fill the purpose of instruction and don’t allow the offense and defense to take the field at the same time. If Ballard is limited or even restricted to the sideline, the mental reps will still suffice before the intensity ratchets up in late May for organized team activities. Ballard is an interesting prospect who is still under the Patriots’ control for three more seasons. He caught 38 passes for 604 yards and four touchdowns for the Giants in 2011, including a big regular-season game against the Patriots with four catches for 67 yards and a game-winning touchdown at Gillette. He caught two passes for 10 yards in the Super Bowl before suffering the knee injury, and he was given a cult-like welcome by the fan base during the postgame celebration. The injury, which also required microfracture surgery, kept Ballard out for the 2012 season. The Giants attempted to place him on injured reserve last June, but the timing of the transaction forced him to clear waivers, which created a huge debate among New York’s decision makers.