A cut-price move to League One side followed last week, and he could prove to be one of the bargains of the summer.
He said: "I'm thrilled to be here.It's such a big club. When you walk through the doors and see the stadium, it says it all really.
"With 20,000 to 30,000 fans in here I'm sure it will be immense. I can't wait to get started.
"They have great fans, the gaffer's a good guy - I'm looking forward to working with him, the coaches and everyone at the club.
"The gaffer is rebuilding his squad, there are a lot of new faces and I'm sure we'll push forward for the League and challenge."
League One rivals Bristol City, who had also agreed a fee with Rangers for MacLean, have insisted that missing out on his signature will not affect their chances of success this season.
Manager Brian Tinnion said: "We already have a number of strikers ready to battle for the front positions.
"MacLean would have been a good long-term investment, but he decided he
didn't want to play for us and that means I am not all that bothered about
losing him."