Ryan is a lot younger than Mike or Mark. He's lefthanded, like Mark, but he will be playing with Mike, who is not lefthanded. Which means that Mike is righthanded. Which is one way to differentiate Mike from Mark. Although it would not help you differentiate Mark from Ryan. But you probably don't need as much help with those two, since it's Mike and Ryan who are on the same team.
Ryan will look more like Mark in a couple weeks because they will both be wearing green and gold. Ryan was born in Cedar Rapids, Iowa. That is if Mark were playing for Oakland, which he isn't. Then Ryan should look like Mike. But neither Mark nor Mike nor Ryan may make the opening day rosters for anyone. So then you will just have to make do.
Since Ryan and Brian don't play on the same continent anymore, you shouldn't be confusing these two guys. But we can't be too sure. Brian was born in Yonkers, New York. So there's Mike from Orange, Mark from Framingham, Ryan from Cedar Rapids, and Brian from Yonkers. They go respectively, right, left, left, right. And they play in Oakland, Los Angeles, Oakland, and Sapporo. Sapporo is just east of Oakland. Or west. It really depends upon how you define east or west based on the 180th meridian.
There were also three Oscar nominations for a movie about this guy:
This is Sweeney Todd, aka the Demon Barber of Fleet Street. He's from London and his birth name wasn't even Sweeney Todd. He's not expected to be with either the Dodgers or Athletics in spring training. This picture leads me to believe that Sweeney is righthanded.
We also have actress Julia Sweeney.
She is not expected to be at spring training for any team this year. I am unsure if she is lefthanded or righthanded as the IMDB does not contain that info. She was born in Spokane. Nine major league baseball players have been born in Spokane, the most notable one being Ryne Sandberg. But also a player named Gary Martz was born in Spokane. He had one at bat in his major league career and it came for the Kansas City Royals on July 8, 1975. That was just about two years after Mike Sweeney, who has so far played his entire major league career for the Royals (until this year when he'll play for Oakland, like Ryan Sweeney) was born in Orange, Calfornia. Mike was born July 22, 1973.
Also, there is John Sweeney (pictured below), who was a member of the House of Representatives from 1997-2007 and represented a district in upstate New York, but it didn't include Yonkers, which is where Brian Sweeney was born. For a while, Sweeney's district included Orange County, New York, which might make you think of Mike Sweeney, who is from Orange, California, but of course, California and New York are different places. Just as Mike and John Sweeney are different people. John Sweeney lost his seat in the 2006 election. He is a Republican, but handedness and political affiliation don't always match up. John Sweeney was born in Troy, New York. Troy used to have major league baseball. However, those Troy teams never had a player named Sweeney on them.