The 26-year-old will move to Spotland Stadium when his contract with Plymouth expires on July 1.
"I'm really pleased to be here and I cannot wait to get started," Alessandra told Rochdale's official website. "I have been a big admirer of the manager Keith Hill for a while."
Alessandra has scored 25 goals in 102 appearances for Plymouth since joining the club from Morecambe in 2013.
Restore Data
| Team | P | W | D | L | F | A | GD | PTS | |
| C | Chesterfield | 46 | 31 | 5 | 10 | 106 | 65 | 41 | 98 |
| 2 | Barnet | 46 | 26 | 8 | 12 | 91 | 60 | 31 | 86 |
| 3 | Bromley | 46 | 22 | 15 | 9 | 73 | 49 | 24 | 81 |
| 4 | AltrinchamAltrincham | 46 | 22 | 11 | 13 | 84 | 59 | 25 | 77 |
| 5 | Solihull MoorsSolihull | 46 | 21 | 13 | 12 | 71 | 62 | 9 | 76 |
| 6 | Gateshead | 46 | 22 | 9 | 15 | 88 | 64 | 24 | 75 |
| 7 | Halifax TownHalifax | 46 | 19 | 14 | 13 | 58 | 50 | 8 | 71 |
| 8 | Aldershot TownAldershot | 46 | 20 | 9 | 17 | 74 | 83 | -9 | 69 |
| 9 | Southend UnitedSouthend | 46 | 21 | 12 | 13 | 70 | 45 | 25 | 65 |
| 10 | Oldham AthleticOldham | 46 | 15 | 18 | 13 | 63 | 60 | 3 | 63 |
| 11 | Rochdale | 46 | 16 | 14 | 16 | 69 | 64 | 5 | 62 |
| 12 | Hartlepool UnitedHartlepool | 46 | 17 | 9 | 20 | 70 | 82 | -12 | 60 |
| 13 | Eastleigh | 46 | 16 | 11 | 19 | 73 | 87 | -14 | 59 |
| 14 | Maidenhead UnitedMaidenhead | 46 | 15 | 13 | 18 | 60 | 67 | -7 | 58 |
| 15 | Dagenham & RedbridgeDag & Red | 46 | 14 | 14 | 18 | 69 | 63 | 6 | 56 |
| 16 | WealdstoneWealdstone | 46 | 15 | 11 | 20 | 60 | 72 | -12 | 56 |
| 17 | Woking | 46 | 15 | 10 | 21 | 49 | 55 | -6 | 55 |
| 18 | Fylde | 46 | 15 | 10 | 21 | 74 | 82 | -8 | 55 |
| 19 | Ebbsfleet | 46 | 14 | 12 | 20 | 59 | 74 | -15 | 54 |
| 20 | York City | 46 | 12 | 17 | 17 | 55 | 69 | -14 | 53 |
| 21 | Boreham WoodBoreham Wood | 46 | 12 | 16 | 18 | 59 | 73 | -14 | 52 |
| 22 | Kidderminster HarriersKidderminster | 46 | 11 | 13 | 22 | 40 | 59 | -19 | 46 |
| 23 | Dorking WanderersDorking | 46 | 12 | 9 | 25 | 54 | 85 | -31 | 45 |
| 24 | Oxford CityOxford City | 46 | 8 | 9 | 29 | 54 | 94 | -40 | 33 |
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