That doesn't mean all their questions have been answered. Not by a long shot.
''You can bring in Babe Ruth to this team or any team, and it doesn't matter,'' general manager Al Avila said. ''What's the key here is that everybody stays healthy and everybody does their part.''
Staying healthy was a problem last year, when Miguel Cabrera, Justin Verlander, Victor Martinez and Anibal Sanchez spent time on the disabled list. So even after adding Upton, Zimmermann and Rodriguez, Detroit has to hope for more production from some of its key holdovers from 2015.
The Tigers stopped in Lansing on Thursday as part of their winter caravan, participating in a meeting hosted by The Associated Press for its members. The buzz from Upton's $132.75 million, six-year agreement this week hasn't worn off yet, but it's hard to say where Detroit ranks in the division after finishing last a season ago.
Upton, Zimmermann and Rodriguez fit nicely onto the roster as replacements for Yoenis Cespedes, David Price and Joakim Soria, all of whom were traded last year. But even with that impressive trio in 2015, the Tigers were a disappointment. A lot went wrong last season, and there are a number of areas where Detroit could use some improvement.
Verlander, for example, made only 20 starts, although he pitched well down the stretch. Sanchez went 10-10 with a 4.99 ERA in 25 starts. A better season from those two could go a long way toward lifting the Tigers up the standings.
Martinez hit .245 in 120 games. Cabrera was much better, winning the American League batting title, but he played only 119 games.
It may be unreasonable to expect full seasons from each of those four players, but they could certainly provide more value than last year. Shane Greene is another Tiger who went through a rough 2015, going 4-8 with a 6.88 ERA before having season-ending surgery to repair a weakened blood vessel in his right shoulder.
Greene allowed one earned run over his first three starts before his season went south in a hurry. It's hard to say how much his health issue affected his performance.
''I think a lot of it had to do with that. Right now, he is 100 percent healthy,'' Avila said. ''When we acquired him, we felt we got a pretty special pitcher, so anything close to what we thought we had is going to be like acquiring a brand new free-agent player.''
''Whenever they tell me to go out there, I'm going to go out there and try to get everybody out,'' Greene said.
One concern that the Tigers are downplaying is the fact that so many of their top hitters - Cabrera, Upton, Ian Kinsler and J.D. Martinez, for example - are right-handed. Outfielder Anthony Gose hits left-handed and figures to get some playing time in center. He could also be an option off the bench late in games, although as Avila pointed out, Detroit is likely to stick with its core of hitters even if the opposition brings in a tough right-hander to match up.
''Are you going to pinch-hit for Miguel Cabrera? No. You're not going to pinch-hit for J.D. Martinez. You're not going to pinch-hit for Ian Kinsler,'' Avila said. ''We have pretty good right-handed hitters, that whether it's a right-handed pitcher or left-handed pitcher, they're going to be in the lineup, they're going to be swinging the bat.''
Follow Noah Trister at www.Twitter.com/noahtrister