The 19-year-old has joined the Shrimps on a one-year deal – with the option of another 12 months – after being released by Preston North End at the end of last season.
Bentley said: “Mike is a young forward who has got good potential. He’s a pacy player and can play wide or down the middle.
“He’s got a good pedigree coming through the ranks at PNE and has had a couple of successful loan moves already.
“We’re looking forward to working with him and helping him develop.”
Howard has previously had spells with Cork City, Stalybridge Celtic and Hednesford Town.