Could this be the end for Roy Halladay?

Philadelphia's Roy Halladay has struggled with his velocity this spring. Kim Klement/USA TODAY Sports

You probably saw that Roy Halladay pitched in a minor league game on Saturday and struggled once again, retiring just seven of the 18 hitters he faced. Jayson Stark was there and wrote:

So only seven hitters actually headed back to the bench without reaching base. Just one of them struck out -- looking, on a fourth-inning changeup, on Halladay's 76th pitch of the day.

More messy details: Halladay threw first-pitch strikes to only eight of 18 hitters. (“That,” muttered one bystander, after another ball one, “isn’t him.”) He induced three swings and misses out of 81 pitches – none on his fastball.

He touched 90 miles per hour on the radar gun once, on his seventh pitch of the day. But mostly, when he delivered his fastball, the guns lit with numbers ranging from 86 to 89.

Needless to say, there is a lot of panic from Phillies fans, and undoubtedly in the Phillies front office, at least behind the scenes. What I'm curious about: Could a pitcher who was the Cy Young winner in 2010 and even better in 2011 lose it so quickly? Could this be the end for Halladay?

We don't know the answer to that, and certainly don't want to make judgments based on six spring training starts, no matter how rough they've been. But it certainly wouldn't be the first time a pitcher of Halladay's caliber goes from Cy Young contender to Cy Yuck in a short period of time. In fact, several great pitchers never declined to the point where they posted an ERA below league average, even at the end. (Halladay's ERA+ last year was 89, where 100 is average and below 100 is worse than average.)

Here's a snapshot of the final years of some great starters of the past 40 years:

Randy Johnson: Johnson never really had a "bad" year until his final season with the Giants in 2009, when he went 8-6 with a 4.88 ERA, an ERA+ of 87.

Pedro Martinez: Effective until injuries took their toll. Had a mediocre 4.48 ERA in 23 starts in 2006, 2.57 ERA in five starts in 2007, 5.61 ERA in 20 starts in 2008 and then a 3.63 ERA in nine starts with the Phillies in 2009.

Greg Maddux: The Smartest Pitcher Who Ever Lived basically had four arcs to his career:

Early (1986-1991): 3.61 ERA

Peak (1992-1998): 2.15 ERA

Downside (1999-2002): 3.07 ERA

Getting Old (2003-2008): 4.13 ERA

Maddux started declining as his strikeout rate dipped and his home run rate went up, probably hand in hand with a decrease in velocity. This is the path I would have projected for Halladay, in the sense that both pitchers relied on movement and supreme command. Maddux didn't have an adjusted ERA below the league average until 2007 (ERA+ of 97 with the Padres) and 2008 (ERA+ of 92 with the Padres/Dodgers). Note that both were better than Halladay's ERA+ in 2012.

Mike Mussina: Retired after winning 20 games with the Yankees in 2008, although he had posted an 88 ERA+ (5.15 ERA) in 2007.

Curt Schilling: Had a bad 2005 when he was injured but had an ERA+ of 120 and 123 his final two seasons.

Roger Clemens: He didn't pitch as many innings, of course, but even in his final season Clemens posted a better-than-average ERA.

Nolan Ryan: Was effective up until his final season (4.88 ERA, 86 ERA+), during which he battled injuries and made just 13 starts, finally blowing out his elbow in September in a start against Seattle in which he allowed five runs (Dann Howitt hit a grand slam) and failed to retire batter. His final pitch to Dave Magadan was reportedly clocked at 98 mph.

Bert Blyleven: Had a 115 ERA+ in 1987 (helping the Twins win the World Series) and then fell to a 75 ERA+ in 1988. Had a strong comeback season with the Angels in 1989 (17-5, 140 ERA+) but then was in effective in 1990, hurt all of 1991 and ineffective in 1992.

Steve Carlton: It was a rapid fall for Carlton. He won the Cy Young Award in 1982 at age 37 and was similarly effective in '83 and '84. Then in 1985, now 40, he went 1-8 in 16 starts, although a 3.33 ERA masked a terrible 48/53 SO/BB ratio. He made 32 starts in 1986, but was terrible (the Phillies released him in June). He famously hung on until 1988, pitching poorly. Obviously, there was an injury of some sort in 1985. Carlton hit the DL after a June 18 start, with a 2.43 ERA at the time. Again, however, he had been somewhat lucky, surviving despite more walks than strikeouts at the time. Whether he was walking more guys because of an injury or a decline in stuff (and afraid to challenge hitters), I'm not sure.

Tom Seaver: Had one bad year in 1982 (5.50 ERA), but was then better than league average from 1983 through 1986. He pitched well with the Red Sox in '86 (111 ERA+) but missed the postseason with foot and back injuries. In June of 1987, he pitched a couple exhibition games with Triple-A Tidewater, wasn't effective, and officially announced his retirement.

Jim Palmer: Still effective until an injury in 1983 limited him to 76.2 innings (4.23 ERA, 94 ERA+) and then 17.2 poor innings in 1984 (9.17 ERA).

Bob Gibson: Still great at age 37 in 1973 (2.77 ERA), less than league average in 1974 (3.83 ERA in 33 starts, although he pitched through a bad knee) and done in 1975 (5.04 ERA).

Halladay turns 36 in May, and arguably pitched better than his 4.49 ERA in 2012 would indicate (3.69 FIP). Maybe there's hope his 2012 is like Schilling's 2005 or Seaver's 1982 and he bounces back with some more good seasons, if not quite at his previous elite level. I think that's one scenario; the other scenario is more ominous, of course, and if you look at the pitchers above, once the decline did begin, none returned to their previous level.

The days of Halladay as a Cy Young contender are likely gone, as evidenced by his struggles with velocity this spring. But if the shoulder doesn't completely blow up, I think he can still be something like a league average pitcher in 2013. I'm not sure that's enough to quiet down the panic in Philly, however.