By Andrew Simon

The job of a Major League manager is not a forgiving one. In a results-oriented business, wins and losses often are the bottom line, and the most important question is, "What have you done for me lately?"

Six teams have changed skippers this offseason, and perhaps no move emphasized the nature of the beast like the Cubs firing Rick Renteria after one season to snag Joe Maddon. After years of rebuilding, Wrigley Field could be ready for a winner again, and Maddon will be expected to help deliver one before long.

Here's a look at five other managers who figure to find themselves under pressure this year.

Brad Ausmus, Tigers

Like the Nationals' Matt Williams, Ausmus is a successful former player who hadn't managed before taking over a win-now team in 2014. And like Williams, Ausmus guided his club to a division title as a rookie skipper before suffering a disappointing first-round playoff exit. Both Detroit and Washington are expected to win again this year, but Ausmus might face the more difficult job going forward.

Free-agent ace Max Scherzer remains unsigned, Justin Verlander is coming off a tough season, Miguel Cabrera is returning from surgery and David Price, Alfredo Simon and Yoenis Cespedes are entering the final year of their contracts. Then there's a problematic bullpen that contributed to the team's downfall in the American League Division Series against the Orioles. Ausmus, whose contract runs through 2016 and includes a '17 option, isn't responsible for putting together the roster. But he will have to find a way to get the most out of it as the Tigers try to stay atop an improving division and get over the hump to capture their first World Series since 1984.

Bud Black, Padres

Expectations often haven't been sky-high during Black's eight seasons in San Diego, but the hiring of general manager A.J. Preller in August has changed that in a hurry. Preller, the fourth GM Black has worked for, has overhauled his roster this offseason, giving Black a much different squad than the one that went 77-85 a year ago. An offense that ranked last in the Majors in many significant categories in 2014 should be bolstered by acquisitions such as outfielders Matt Kemp, Wil Myers and Justin Upton, and catcher Derek Norris.

Those types of splashy additions -- and the accompanying bump in payroll -- will ratchet up the pressure on Black, whose contract runs through 2015. During his tenure, San Diego has gone 617-680 (.476), posted a winning record only twice, finished above third in the NL West once and never made the playoffs, despite close calls in '07 and '10 (when Black was named NL Manager of the Year). As well respected as Black is, the Padres' new front office hasn't turned up the Hot Stove and sacrificed a slew of prospects just for a fifth consecutive sub-.500 campaign.

Terry Collins, Mets

At last month's Winter Meetings in San Diego, Collins did nothing to downplay the suggestion that he is on the hot seat entering 2015. While the veteran skipper said he has tried to preach and practice patience throughout his four years in New York, it's now "time to step up."

Collins hasn't made the playoffs in 10 years as a big league skipper, and the Mets have gone 304-344 (.469) with him at the helm, finishing between 74 and 79 victories each season. Of course, Collins has been handed greatly flawed rosters during that time. While outfielder Michael Cuddyer has been the club's lone significant addition so far this offseason, a rebound from third baseman David Wright and the returns of starter Matt Harvey and reliever Bobby Parnell from injury could help the Mets contend for their first postseason berth since '06. If they don't, Collins might find himself out of time.

Don Mattingly, Dodgers

Just looking at the raw numbers, Mattingly would seem to be on solid footing. Los Angeles has finished above .500 in each of his four seasons, gradually rising from 82 to 94 victories and winning two straight division titles. On the other hand, both of those clubs fell shy of the World Series, leaving the Dodgers to continue their pursuit of their first championship since 1988.

Pressure is a constant when you manage a big-market club with a payroll sitting well north of $200 million. That only increased this offseason, when ownership brought in a front-office dream team highlighted by Andrew Friedman. The organization's new president of baseball operations committed strongly to Mattingly -- and passed up a chance to bring in Maddon -- back in October. But he also has no attachment to Mattingly and already has showed a willingness to make bold changes, with moves such as the trade of Kemp to a division foe. It remains to be seen how the manager and front office will mesh, but with Mattingly's contract set to expire after the 2016 season, he might need to take the Dodgers all the way to prevent another round of job speculation.

Robin Ventura, White Sox

General manager Rick Hahn said Ventura has done "an excellent job," despite presiding over 188 losses over the past two seasons. After all, the Sox have been working through a rebuilding effort since going 85-77 in Ventura's debut season. The former All-Star third baseman even got a multiyear contract extension last January, so he won't enter 2015 as a lame duck.

He will enter it with a revamped roster, as the White Sox have been one of the most active teams this offseason. By adding first baseman Adam LaRoche, left fielder Melky Cabrera, starter Jeff Samardzija and closer David Robertson, among others, Hahn has set up Chicago to make a serious run at breaking its six-year playoff drought. But the talent influx also will bring more emphasis on the win column as Ventura tries to improve his .455 career winning percentage.

***

Andrew Simon is a contributor to Sports on Earth and a reporter for MLB.com.